



































































THE UNIVERSITY OF CHICAGO 


AH ECOLOGICAL SURVEY OF THE PORCUPINE MOUNTAINS 


A DISSERTATION 
SUBMITTED TO THE FACULTY 
OF TEE OGDEN GRADUATE SCHOOL OF SCIEHCE 
IH CANDIDACY FOR THE DEGREE OF 
DOCTOR OF PHILOSOPHY 


DEPARTMENT OF BOTANY 



CHICAGO.ILLINOIS 


NOVEMBER. 1923 





ftp;.; * 

^ , A 





1 - MAR 2 5 

Knpy 1968 








INTRODUCTION 


1 


EARL IER INVESTIGATIONS III THE PORCUPINE MOUNTAINS-3 

LOCATION AND PHYSIOGRAPHY---5 

CLIMaTE OP THE REGION-7 

THE CLIMAX FORMATIONS-11 

I. THE HEMLOCK CLIMAX-12 

A. Aspect of the forest - -- -- -- -- -- -12 

B. Composition and dynamics of the forest - - - 16 

1. Consideration of individual species - - 17 

2. Quadrat studies ------------22 

3. Initial physical factors and 

competition ------------25 

4* Equilibrium at any point --------28 

C« Successions leading to the hemlock climax - - 29 

1. Primary successions ----------29 

a. Physiographic influences ----- 29 

b* The shore successions -------31 

Types of shore - - '- - v- ----- 34 

2* Secondary successions in the Hemlock 
climax - ----------- 


36 

































































* 

' ' • 

* 


* 











Page 

II. THE MAPLE CLIMAX- 38 

A. General physiographic features ------- 39 

B. Successions relations - -- -- -- — - - 41 

I. Xeruroh successions on the first range - 41 

(1) Summit of the range -------42 

fa) Ecological factors ----- 42 
(b) The plant associations - - - 43 
fc) Quadrat studies -------47 

(2) The escarpment and its asso¬ 

ciations ----------50 

(3) The talus slope ---------53 

f4) Forest below the talus ------ 58 

II. Hydrarch successions in the valley 

of Carp River -----------61 

a. Carp River ------------64 

b• Carp Lake ------------66 

o. Flood plain -----------69 

SUMMARY-71 

REFERENCES - 77,78,79,80 

















HI ... 


































■ 

| . - . ' 


" 





• 









KA'ILK RJVK 


•SXMnnmr 




psprjT^; 

m 


J 


Map showing general position of the Porcupine Moun¬ 
tains in Ontonagon County, Michigan. 

































































































INTRODUCTION 


In his classic article on the climax forest of 
Isle Royale, Lake Superior, Cooper (5) refers to the trans- 
itional zone between the two great phytogeographic regions - 
the northeastern conifer forest and the eastern deciduous 
forest. Certain features of both regions, he says, are 
found in the southwestern portion of the island; but he 
did not carry out his first intention of tracing the relat¬ 
ions between them. On the mainland of Michigan to the south, 
the maple forest is well developed, especially at certain 
inland points. Areas near the coast, however, may show 
many transitional features, such as occur in the Porcupine 
Mountains, which are about 125 km. south southwest of Isle 
Royale. These so-called mountains, which are really 
prominent hills or hilly ridges, represent the highest points 
of land reached in the Upper Peninsula. As Leverett (20) 
points out, they are "the most conspicuous features in this 
entire area, for they rise on their north slope very abruptly 
from the shore of Lake Superior to a height of 1400 feet 
above the lake". 

The purpose of this ecological survey was to make 
a careful study of the climax formation of the region, in 
eluding their relations to each other, and to correlate, 
if possible, the various plant associations occurring within 
them. 








. 


' 

. 

- 




, 

1 






. j 




. " 

* 

* 

, . *i : 

. 

‘ . 










- 




The Porcupine Mountains consist roughly of three 
ranges of hills, paralleling the coast (fig. 1), that nearest 
the shore b&ing the most rugged. Back of these lies a table¬ 
land stretching south to the Gogebic Range. 

It was not found possible to examine all of this 
territory; nor does it seem essential to an understanding of 
the vegetational development of the region. Practically all 
the detail studies were made in connection with the first 
range, and the valley of Carp River behind it. It must be 
admitted that this near-shore region received most attention 
because of its greater accessibility, yet aside from this it 
seemed of major importance for the following reasons: (1) on 
account of the pioneer conditions found on the first range, 
where the summit still remains unclaimed by vegetational 
development, (2) on account of the proximity of Lake Superior, 
permitting the observation of various stages of succession 
along the shore, (3) the proximity of a comparatively high 
altitude (for the region) to the wind-swept surface of Lake 
Superior, giving a definiteness to the larger problems of 
vegetation, (4) a forest covering which gives it unusual 
value for a study of the relation between two climax formations, 
(5) opportunity for observing praotically primeval forest 
conditions. 

Field work was carried out in the sunnier of 1922. 
Headquarters were first established at a point on Union 












, 





































, 

■' 

















1 


























* 















Map showing a portion of the Porcupine Mountains. 

























































































































































| ' 
















' 




















































.... V _ 












































- 


































-3- 


Bay (Sec. 16, T. 51 H» H 42 W«). This was found to be the 
most convenient location for the examination of the shore 
line and the hemlock forest of the north slope. Later, head¬ 
quarters were located on the site of an old mining property 
near Carp Lake. All the work in connection with Carp River 
valley and the summit of the range was done from this point. 

I wish to express my appreciation of the encourage¬ 
ment and co-operation of Dr. H. C. Cowles of the University 
of Chicago, under whose direction the work was undertaken. 

I also wish to thank Dr. Geo. D. Puller of the same institution 
for suggestions in regard to the method of work. To the follow 
ing gentlemen, I desire likewise to extend my thanks. Dr. A. J. 
Grout of New Brighton, II. Y. , for the determination of about 
45 species of moss. Dr. Bruce Pink of Miami University, Ohio, 
for the determination of about 60 species of lichens, and Dr. 

E. A. Bessey of the Michigan Agricultural College, for assist¬ 
ance in various ways. The nomenclature used in connection with 
the pteridophytea and spermatophytes is that of GRAY'S MANUAL, 
seventh edition. 

EARLIER INVESTIGATIONS IN THE PORCUPINE MOUNTAINS- 

The early interest attaching to an exploration of 
the mountains was based on the prospect of finding copper. 
Indications of this interest are shown in the abandoned 
shafts and wordings in various parts of the region. In 1848 






. 




. 




* ■ 




. 

... 

. 

o 2 

. 

, . V • > i'i . . • 

' - - ' 

. 

. jI > ' :r r; s 







• ■ . • • . • ; 









Pig. 1. - Carp Lake from top of firat range, looking 
southwest: second and third ranges in the distance: escarp 
ment of first range extending H. S. W. (extreme right); 
outlet of lake at far end. 














































































































#i 9 % 




































































































-4- 


the mountains were visited by W. D. Whitney (11) acting as 
botanist on a government expedition in charge of J. W. Foster. 
The following year, several places on the south shore of Lake 
Superior were visited - as far west - Whitney says, as the 
Ontonagon Valley and Carp River, both being in the vicinity 
of the Porcupines. In the second report on the region (IP), 
which was published in 1851, Whitney gives a list of plants 
seen in the Upper Peninsula, including some from Isle Royale. 
This list, being very general, gives no clue as to what 
species were observed in the Porcupine Mountains. In 
JACKSON'S LAKE SUPERIORS), published in 1849, Bela Hubbard, 
a geologist, in discussing the origin and character of the 
soil in the Porcupines, points out that the sugar maple pre¬ 
dominates throughout the elevated portions, 'while hemlock is 
the prevailing tree upon the lower lands. 

During the next fifty years, apparently little was 
done in the way of botanical investigation in this region. 

In the summer of 1903, F. E. Wright (£8), Assistant State 
Geologist, continued the work, earlier begun under the 
direction of Dr. L. L. Hubbard, of preparing data for an 
accurate geological report and map of the mountains. During 
a part of this time he was accompanied by Dr. A. G. Ruthven 

of the University of Michigan, who became interested in the 
biological aspects of the country. In 1904 and 1905, the 






■ 

. 

1 :r ‘ 

• ■' - 

. 

' 

. 

. ' 

. ' • • • • • • 

.... - * 

, 





. 

. . 

. .‘V ■ ‘ ' ft - : - 






5- 


University Museum sent purties to northern Michigan to make 
biological studies in the Porcupine Mountains and in Isle 
Royale. One party, led by ])r. Ruthven, spent one month in 
the Porcupines and the remainder of the season on Isle Royale. 
The report of this expedition fl) came out in 1905* It covers 
both regions, listing 91 species of plants, and notes the 
ecological distribution of the more important species. 

A list of over 600 plants found in the neighboring 
county of Gogebic should be mentioned. It was based on work 
done by Dr. £• ii. Bessey and the writer (10) during portions 
of the summers of 1919 and 1920. 

LOCATION AND PHYSIOGRAPHY. 

The Porcupine Mountains are in Ontonagon County in 
the Northern Peninsula of Michigan, in lat. 47 0., long. 90 w. 
(see map). Thoir unique position, close to the south shore of 
Lake Superior, has already been pointod out. Thoy reach a maxi- 
mum altitude of 616 m. above sea level or 435 tn. above the level 
of the lake. The top of the first range or ridge comes within 2 
km. of tho shore. Its north slope is rather gentle, but becomes 
increasingly stoop as one approaches the summit, finally 
reaching a height of 275 m. abovo the lake in sec. 14, T. 51 B. 
R. 43 W. There is then a sudden descent of about 120 m. to 
the valley Of Carp River, half of this descent bOfcng, in 
places, vertical rock face, at tho base of the cliff there 




























/ 




















. 





























» 














Pig. 2. - Geological map of a portion of the 
Porcupine Mountains, showing their relation to the 
Keweenaw Series to the south. (After Irving). 
























































































































7 














. - . : 






. 










- 6 - 


i8 a talus slope extending in places several hundred meters 
down the side of the valley. This great cliff extends for 
a distance of about 10 km. across T. hi U. R. 43 W. It is 
interesting to note Poster’s impressions on first seeing 
this great outcropping of rock in 1848. He says "Suddenly 
the traveler finds himself on the brink of a precipice five 
hundred feet deep, at the base of which lies a small laice, 
so sheltered and hemmed in by the surrounding mountains that 
the wind rarely ripples its surface. Gloomy evergreens skirt 
its shores, whose long and pendant branches are so faithfully 
reflected on the surface that the eye can with difficulty 
determine where the water ends and the shore begins. Prom 
this lake flows the Carp River, and the beholder occasionally 
catches a glimpse of its waters as they wind through the 
narrow valley towards the great reservoir". 

Geologioally, the mountains form a crescent-shaped 
off-shoot or spur from the main range to the south (fig. 2). 
This latter extends from Keweenaw Point southwest to Wisconsin, 
including the well-known iron and copper ranges of the Keweenaw 
Series. The ranges of the Porcupines consist largely of 
eruptive rocks with interbedded sandstones and conglomerates, 
the strata tilted from 30° - 40°. They represent part of a 
pre-Cambrian upheaval, probably during early Proterozoic time. 
The present system of hills forms a comparatively small 




■ $ 4 ; ' •: 1 i • '* •• * ' •• • ' ° 

, * , . ' . " i r •:*•; ‘ * •• 

’ . ■ 

r j, ' ' : I . • 4: < 

■ ‘ 

• ' ’ 

■ 

. • 










Pig. 3. 


Geological sections illustrating the struc 


ure of the Porcupine Mountains, (/iftor Irving) 




















. 













- 7 - 


portion ( fig. 3) of the original land mass, the rest having 
been removed by erosion during a very long period of time. 

At the beginning of the glacial period, the general 
topography was probably much the same as at present. The 
mountains were laid bare at a relatively early date, mating a 
cusp in the ice front, presumably between the Warren and Algon¬ 
quin stages. According to Lane (19) the water was ponded on 
the north side of the mountains to a depth of 171 m. above the 
present surface of Late Superior and on the south side at least 
49 m. higher than this, the drainage being toward the Mississippi. 
Old beach lines on the north slopes show successive stages in 
the height of the late, where the late level was more or less 
stationary. 

From what has been said, it is evident that the 
highest level lies bact of the first range, though the latter 
is much the most rugged. The rough topography is, in general, 
conditioned by the geologic structure of the region. The main 
drainage lines are occupied by the Carp and Little Carp rivers, 
which flow roughly southwest. These parallel the general 
direction of the ridges, and finally turn northwest, emptying 
into Lake Superior. A portion of the drainage is also east and 
southeast into the valley of Iron Eivor. 

CLIMATE OF THE HBOIOH. 

The following data were obtained through the 
courtesy of the U. 3. Weather Bureau at East Lansing; see also 








' • * 


























■ 






. ■ ’■ 




















* 


























' 












report by Seeley (£4). It is believed that tables I and II 
taken together give a fair index of the olimatio conditions. 
Bergland, representing inland conditions, is about £7 km. 
south southeast of Carp Lake; it has an elevation of £15 m. 
above the surface of Lake Superior. Ontonagon is situated 
at the mouth of the Ontonagon River, 3£ km. east of Bergland. 
The tables show that the mean temperature for the year is 
very nearly the same for both places. 

-TABLE I- 

MEAH TEMPERATURE AT BERGLAHD FOR 11 YEARS 


°C — Jan. 

Feb. 

Mar. 

Apr. 

May 

June 

-1£.9 

-11.4 

-4.1 

4.1 

10.5 

16.3 

°C — July 

Aug. 

Sept • 

Oct. 

Uov • 

Dec. Yr. 

18.6 

16.9 

1£.7 

6.8 

-0.£ 

-7.7 4.1 

-TABLE II- 

MEaH TEMPERATURE AT Oil TO 1JAG OH 

FOR 7 

YEARS 

°C — Jan. 

Feb. 

Mar. 

Apr. 

May 

June 

-9.3 

-10.8 

-3.5 

3.8 

9 .£ 

13.5 

*C — July 

AUg. 

Sept. 

Oct. 

Hov. 

Dec. Yr. 

17.8 

17.4 

14.0 

9.4 

0.7 

-5.8 4.£ 
























dieroriees in "the average monthly temperatures 
0f the tm) P^cea indicate the probable moderating influence 
Ox ^Lq J.arge body of water* ^he average maximum temperature 
for 5 years at Ontonagon was 34.6° C. and the average minimum 
-^‘•7 C. The mean monthly temperature at Bergland for 11 
ye&iii was above 0 C. for 7 months of the year, beginning with 
April, and the mean monthly minimum above this for 6 months, 
beginning with Hay. Tables prepared by the U. 3. Weather 
Bureau show that the average date of the last killing frost 
in spring is June 9, while that of the first Killing frost in 
the fall is 3optember 16, giving 89 days as the average length 
Ox uhe growing season. In this region the isotherms parallel 
the shore line, and the average temperature of points along 
the coat is several degrees warmer than inland points a few 
miles further back. During the hot summer months, however, 
the isotherms move back from the shore, so that the discrepancy 
between shore and inland conditions is not so great. 


-TABLJ5 III- 

AViSRAGiS MONTHLY PRJSCIPITATIOU AT B3RGLABD FOE 11 Y&ARS 


— Jan. 

Feb. 

Mar. 

Apr. 

May 

June 

cm 4.05 

3.26 

4.27 

4.70 

7.86 

8.87 

July 

Aug. 

Sopt. 

Oct. 

Ilov. 

Dec. Yr. 


















































- s i 















































-10 


-TABLE IV- 

AVERASE MONTHLY PRECIPITATION AT ONTONAGON FOR 6 YEARS 


_Jan- 

Feb. 

liar. 

,.pr • 

May 

June 

cm -- 6.96 

4-66 

3.89 

2.61 

6.72 

6.25 

— July 

iH* 

Sept. 

Oot. 

Nov. 

Beo. Yr. 

cm — 11.37 

8.42 

9.27 

4.37 

5.86 

7.02 74.57 


1.&0 above data, while not extending over as groat a 
period of time as might be deuxrublo, would seem to indicate 
that the average yearly rainfall for the region is about 76 
cm* The figures show that the average precipitation along 
the coast during the months from November to February is 305? 
greater than the precipitation at Bergland 26 ion. bacic from 
the coast- This may help tc explain certain striking differ¬ 
ences between the vegetation near the shore and that further 
inland- Slightly more than one-half the average rainfall 
occurs during the 5 months of the growing season (from May 
to September), apparently coming earlier in the season at 
inland points- The greatest average precipitation was in 
July. 

The average number of cloudy days per month for 5 
































. 



























































• • 



- 

























































Fig* 4. - iSxfJorior view of hemlock climax along a 
"forty” lino where the timber hue been cut: two eugar 
maples to the right, largo hemlock in the background, 
salmon berry and three email hemlocks in the fore¬ 
ground; elevation about 100 m. above Lake Superior. 


\ 






























































































































































■ 



















































































































































































-u 


/. 


years at Ontonagon was 14, and partly cloudy 5, leaving 
an average of 137 clear days for the year. The prevailing 
direction of the wind at the same station is from the 
northwest, often veering around from the west. 

The extent and ruggednesa of the Porcupines allow 
for much local variation. The above climatic data axe not 
meant to be more than general. Their character accords with 
the general mesophytic character of the vegetation in its 
larger aspects. 


THE CLIMAX FORMATIONS. 

There are two climax plant formations covering 
the ranges of the Porcupine Mountains. On the north slope 
of the first range occurs a typical hemlock: forest. This 
gradually merges into a maple forest near the top of the 
slope. From this point maple forms the climax formation 
on the ranges to the south, though scattered patches of 
hemlock: occur on the lower slopes. Any interpretation 
of the vegetation of the region must take into account 
the relation between these two formations, their relative 
position with respect to the larger physiographic features 
and the successions leading up to them. In this paper 
the hemlock climax will be considered first. 


• , • . ■ . . 

. 

\X 

. 

. 




i 

. 

, • 

. 




- 12 - 


I. Tim HJ&ILOCiC CL mAX 

This is apparently the most mesophytic formation 
of the region. Its most typical development is on the lower 
half of the north slope of the first range. It is composed 
largely of three tree species: Tsuga canadonsis (L.) Carr, 
(hemlock) , Acer ^accharum Harsh, (sugar maple) and Betula 
lutea Michx. f. (yellow birch). At the lower levels near 
the lake shore, the forest is almost entirely hemlock:, while 
near the top of the ridge it mergest into the less mosophytic 
maple forest. 

Intensive studies were made at various points in 
the forest with a view to determining the relations between 
the three principal species. The life habits of each, from 
the seedling stage up, were studied as closely as time 
permitted. Interrelations of the species were also studied 
by means of quadrats and windfall areas. 

A. Aspect of the Forest. 

At first sight the forest appears to be almost 
a pure stand of hemlock. The boles are conspicuous below, 
but the upper portions of the trees, which are 25-30 m. or 
mere tall, form a dense mass of interlaced foliage, with a 
ragged skyline. Here and there are occasional trees of 
yellow birch, with more open tops; also a few tall spindling 
maples, devoid of foliage, excepting near the summit, and 










. 


. ' «' • ■ 

♦ . . . V 

-• » •— - 

, . 

• - ' ■ * - ... 

. 

>. X> 

. 


! X- ■ ' .*ra |l 

. ; r i . - i . t VO ' ot c\ A 

. v; . ' 

• • ■ ' ■ i. • ' •: - r 

• . .. . . • .: S - • *> ' • ? T .■ • ;,f ; >« 

•• ■ . 

. , • •■■■, <••• 


- . ■ r • ' .n . B j 


























I 



Pig. 5. - Showa distribution of yellow 
birch and maple, the conifers being ramoved; 
trees in the foreground are mostly maples; 
looking northeast toward Lake Superior; edge 
of forest to left; note abundant growth of 
aalmon berry aa a ground cover. 

























































« ** • ' 








- 























-13- 


often indicating by the presence of dead twigg, the com¬ 
petition to which they are subjected. 

In section 16, T* 51 K* R. 42 W., the hemlock: had 
been removed from certain "forties", making it possible to 
obtain a view of the general composition of the forest from 
the outside. This is shown in fig* 4. The three species 
mentioned are practically the only ones in evidence from 
an exterior view of a soction made in this part of the 
forest. Other large tree species, of less common occurrence, 
will be considered later. 

In the area cut over, referred to above, only the 
conifers had been removed, leaving the two principal deciduous 
species standing, as shown in fig* 5* This gave an opportunity 
to estimate the relative distribution and character of the 
latter. An estimate was also made of the comparative number 
of species in the forest having a diameter not less than 
1.5 dm. This was done by listing the individuals in a belt 
transect 220 m. long and 10 m. wide. It resulted In the 
following data so far as the principal species is concerned: 
hemlock, 80.5$; maple, 13.6$; yellow birch, 4.5$; basswood, 

1 . 5 $* 

On entering tho forest, one is impressed with the 
apparent age and maturity of the trees (fig* 6). The light 
is much reduced by the dense canopy above, formed principally 


• *'> , 1 - 

. r . / < 

..1 ’ . . • • • * . . ' ■ - ' 

I *. ; .: . . / . ' . . . J . - ■ • 

*V :■ : • •. : ■ , ■ * ’ - • . : • -• 


. . ; > 

.. ; 

l. 

* 

; i :j - j .. ivp 

• • . . . • ’ 

• .■ . ... v ‘ 

. ' * . - . 


' • • . . . ■ . X 






; • • . . 

-i u.' ' , • * j J - - 




• • - . ••.. - v . : . ;•.. r. . . 

• r •. « . . ■ . 

, ft-v < ' \ .. 








Fig. 6. - Interior view of Liosophytio 
forest (see. 16, T. 61 K* R. 42 W#): trees 
mostly hemlook; a largo yellow biroh in 
foreground at left; a portion of the orown 
of a maple at the right; looking north to¬ 
ward Lake Superior; note gentlo slope. 























/ 


*- 
























' - 




"« ■ 






























• -- 






-• 










- * 



















. 




■ 





















14- 


by the fine spray of the hemlocks. An examination over a 
large area shows considerable diversity in regard to light 
conditions, the differences boing due to more or less open 
areas caused by windfalls of varying ages. In reality the 
forest may be considered as a patchwork of these windfalls, 
which are ever appearing, maturing their growth and con¬ 
sequently producing a general shift in the position of the 
better lighted areas. 

The forest floor is rather uneven and on the whole 
well drained, the general direction of the gullies being 
north (towards Lake Superior). A few of these gullies are 
occupied by small streams, even during the summer months, 
while others contain no running water* but are very moist, 
so that the moisture content of the soil is quite variable 
for different portions of the forest. This seems to be the 
controlling factor in causing certain departures from the 
ordinary composition of the forest (fig. 7). 

There is comparatively little shrubby vegetation 
in the dense hemlock forest. Of the few shrubs found, 
probably Lonicera canadensis Harsh, (bush honeysuckle) is 
the most shade tolerant. The most important ecologically 
is Rub us parvlflorus Ifutt. (salmon berry), which is very 
quick to appear where an opening admits even a little more 
light to the forest floor. The bottoms of shallow draws 

















. • 

i - • . •. ' . 

■J • « - " ‘ - ■ ' • 

r 

3 / . . : . 

> <v ' i . .) 'j. ; iX 

- ; '■ : : ; ■ : • .' *• •. • .. 




r? ' ‘ * w L ; ■ ..=• V 


‘ . • : ,• ... 


: : • , ■ • *• 

- ’ - • i • . . . . 

* * ■ ‘ '■ -■ 5 . X r* j 


•• • ' ••• -• ' • ■ 0 . fl'irv 

5 ‘ •' • ' . • wi :' v .; :: . - ■ . 

. ■ ■ 

. ' ‘ . 










Pig* V. - Shows a *781tor, more open por¬ 
tion of the forest, in which tho predominant 
large tree is arbor vitae: in the foreground, 
salmon borry, and 30 idlings of maple, balsam, 
and white spruce; other tree seedlings ob¬ 
served vjere yellow birch, basswood, and whito 


ash • 












. 






* 






are sometimes covered with it, evon when partially shaded. 

Large numbers of woody sugar maple seedlings from 2-6 dm. 
tall often form a shrubby growth of considerable ecological 
importance. Other shrubs and shrubby trees found more or 
lees frequently in or near the border of windfall areas are: 
Acer spicatum Lem. (mountain maple), Amelanchier canadensis (L.) 
lledie. (June berry), Salix rostrata Richards (Bebb f s 7,/illow) , 
Prunus Virginians L. (choke cherry), Cornus alternifolia L. f. 
(alternate-leaved dogwood) , and Corylus rostrata Ait. (beaked 
hazelnut). 

In general, tfte herbaceous vegetation forms a closer 
index to the moisture content of the surface soil than the 
woody vegetation.. The most widely spread and shade-tolerant 
species of the hemlock forest is Aralla nudicaulis L. (wild 
sarsaoarilla)• Others of rather general distribution are: 

Galium trifloru m Kichx. (bedstraw), A ster macrophyllus L. 
(large-leaved aster), Clintonia bo realis (Ait) Raf. , Pitched!a 
repens L. (partridge-berry), Oxalia Acotosolla L. (wood sorrel^, 
Trientalis americana (Pers.) Pursh. (star-flower), Lycopodium 
ennotinum L. (stiff club moss) and Aspidium spinulosum (0. F. 
Mtlller) Sw- var. intermedium (Muhl.) P. C. Eaton. The follow¬ 
ing list is not so characteristic, but it includes some which 
are frequently found along water courses or low ground: 

Asplenium Pilix-femina (L.) Bernh. (lady fern), Onocloa 













































- 









, 

■■ li. - . u 

J' ' V ■ ■ ; - • V --W* ■ ■ 'V f* •’ • 

' - • ’j- : ;• ’ “ . i‘ . I 3. v: ■ $ . . o;.' ri >* ; 

, 

s . ■ > r . 1 r. ' 

i. • . ■ - . 

■ 

■ . , 

* t . ' ,*»• /• . *4 . 1 - S'. :) 

• ..... u 

’ ' • - t _ . . - • - : 

■ ’ • :.. . . . , rr - ■■ , 






• ; •• : : ■ * " ' -i i > . _ : 

■ ■ • ' l 

' ' .... » • * - . '• • • - I - : , ) 

• .. , , - • • . : . • -■ * 

. • - ■ • . •: _..1 .... _ . _ 

. . . : 

. 

: • -l • >: • \ j..:.- . . • 

• ' • > . - i . ; . .. 



























?%. Q. - Stand of sugar muplo, approximately 7a m. 

north of the summit of the ridgo in see. 14. hi n. H. 
43 tho trees here aro somewhat larger than is typioal; 
note comparatively dear forest floor; maple seedlings 


in tho foreground. 


























































































' * * : tt 




' 





' 






























-16 


Struthiopteris (L.) Hoff, (ostrich fern), Phegopteris poly - 
podioidea Fee (beech fern), Circaoa alpina L. (enchanter's 
nightshade), Solidago latifolia L. (broad-loaved goldenrod), 
Mitella nuda L. (bishop's cap), Stroptopus roseus Itichx. 
(twisted-stalk), Cornua canadensis L. (dwarf cornel), 

> 

Chinaphlla uribellata (L.) Hutt. (pipsiosowa), Pronanthea alba 
L. (rattlesnake-root). Aster paniculatus Lam., Kununculua 
recurvatus Poir. (rough cinquefoil). 

Several species of moss and lichens lend color to 
the general aspect of the forest. One of the most conspicuous 
is Ileokera pennata (L.) Hedw., forming green mats on the sides 
of the trees and ofton extending several meters up. On rotting 
logs in windfalls and along small crooks occur such moss species 
as Brachytheeium salebrosum (Hoffin.) Bryol., Plagiothecium 
turfaceura lindb., Kypnum Crista-Custrensis L., and the lichen 
3ticta pulmonariu (L.) Schaer. 

B. Composition and dynamics of the forest. 

As before indicated, one of the major problems in 
connection with the forest of the north slope, is to account 
for its composition, especially as regards the relation be¬ 
tween the hemlock and maple. As one ascends the slope the 
maple contingent becomes greater and the hemlock less, so that 
finally there appears to be at first sight an almost pure stand 







































T .1) 

■ 

* ¥ j- ' 


. * 






. 

i . . • 










» . 








f 

• - ■ ; ! , •, ■ • .. - ... 









• 


- 




/ 
























































■17- 


of maple (fig* 8). 

The fact that the most conspicuous stand of almost 
pure hemlock forest is to be found on the north slope of the 
first range within about 10G0 m- of the shore is probably 
to be accounted for by climatic conditions, rather than by 
differences in character of soil. The present composition 
of the hemlock climax has undoubtedly existed for centuries. 
In other words, the forest as a whole is in equilibrium as 
regards the relative numbers of the component tree species 
at a given altitude. A casual observation of the stages of 
succession in a windfall area, might lead one to think that 
maple should be the predominant tree (fig. 9). For this 
reason it seemed necessary to consider carefully such 
questions as the rate of growth, habit, shade tolerance, etc. 
of the more important species, and the relationship of their 
development, as shown by quadrat studies. 

1. COlf SID .SHAT ION OF INDIVIDUAL SPSCIiiS. 

T3UGA CANADi&NSIS (hemlock).- This species continues 
to grow in diameter many years after its top has leached the 
crown of the forest, the result being that the stand consists 
of individuals with great diversity in their ages. Sapling 
stages are quite common, though their growth is often vory 
slow. The tolerance of all stages for weak light explains 















« 


.; . . iV • • t « • j 

■ 

■, .. . ;.t y , , ■ . • ' ll ■ ' • ' ' . 1 ' 

. 

■ 

: ; : • - \ ■ ■ 

i i. ' . • .. ■ - > ■ - : 

r - ' - - ; 

. • : 

... ; ■ - * ■ ■ 

. 

: ., • • • • • - ' ' • • 

- - • ■ - 

- 










Pig* 9. - Seedlings of sugar maple in 
hemlock forest: thooo pioturod ara 1*5 • S.O 
dm* high, there being approximately 40 in¬ 
dividuals per square meter* 













































































. 

. 

















. 




-1C 


the dominance of the species over maple, its nearest com- 
petltor in the forest. On account of this tolerance, 
suppression at eome stage of its earlier growth is the rule 
rather than the exception. 

The tree usually seeds at intervals of every & or 
3 years, and in spite of reduced fertility, many more seedlings 
start than are able to mature, even though they are not notice¬ 
ably abundant, us in the case of the maple. The production 
of seeds and seedlings is therefore not the critical fuetor 
in the regeneration of either species. 

The species is extremely sensitive to sudden changes 
in the density of the forest, and seedlings respond quickly 
in rate of growth to alight increases in the amount of light 
admitted, but they are killed by too much light, and therefore 
the tree will not take a central position in an open vyiridfall 
unless it is sheltered by fast'er growing species. On account 
of its shallow root system, it is very susceptible to surface 
fires. 

ACKR SACCHaKUM (sugar maple). - This species, as it 
occurs in the hemlock climaK, is tall and slim and free of 
limbs except near the top. The trees are apparently healthy, 
though all of them have undoubtedly suffered more or lees 
suppression. As already noted, the seedlings occur in such 
numbers that a superficial observation might lead one to 


• • ■ . ; 1. y. 

9 

. . . .■ ■ ; . ..■ • .... . . • i:- 

, . - . • • •• ; 

• fc.Ji ■ V C ' f .• ' . I 

v • ■ j u /, •' ; ... v • * : 

... ■ 

• . s j ? ; • 

• . . - , . -i . . 


■ ■ 


. • ■ i; . v i. 1 . .. * \ . : . a j \ : 

. Vi: -- "... > : w 4 . : y .j ' .. 

•!V > • - . i ’< • >: ■ *i. 




'■ k . : . - ... 

r ■ i. . . : .. ^ .1 

^ 7 ■. i . \ , . : • . .. .' ' 


. 1 ... • • : . •• - ' ) : V .j. . . 

~ ’ -i''. - - ; - , 25 i* 

... 

• u ■' .. 

: ' .... . ; . • • • . . j •: •• 

• v ■ ■ ■ ■ ■ : - r .*v. 



Pig. 10. - View along an old wood 
road, which here acta ae an artificial 
•windfall: on each aide of the road there 
ie a donee growth of young maplee, E - 6 
ra« high; ualmon berry in the foreground. 







































































— 














' 































19- 


conelude that the forest would, in a few generations, be¬ 
come a pure stand of maple. Closer observation soon shows 
that a very small percentage of these ever mature* Accord¬ 
ing to Frothingham (13) the trees seed every 3-5 years 
under forest conditions; and oven-aged groups of very close- 
standing seedlings are of common occurrence* They prefer 
mapia leaf-mold and avoid areas covered with hemlock needles* 
The close and abundant growth of the seedlings results in 
such severe competition that the individuals are weakened and 
most of them succumb to suppresion or disease. However, the 
seedlings are very tolerant of shade conditions, arid a few 
here and there are able to persist, and take advantage of the 
increased light occasioned by a windfall* Indeed, the relative 
stand of maple and other hardwoods in the hemlock climax seems 
mainly to be conditioned by the number of windfall areas. In 
such areas. Hubus parviflorus often forms a ground cover, 
affording more or less protection to young seedlings which are 
exposed to strong sunlight. 

BKTULA LUSHA (yellow birch). - This tree, coming 
next to maple in its distribution, is an important element 
in the climax formation. In the forest it becomes slim and 
tall with a clean bole, having limbs only near the top. A 
specimen was observed along a woods road about 30 m. tall, 
ivith a broad crown, occupying half the height; this tree was 




. r • . • ■ . • - - : ' ; • 

, .. • • • ■ J - 

: 'A* - 1 

- ■ • , . ■ ' 1 ' •' ■ •' : - ' 1 

» 

■ . , ■ }Q • ’ • • • 1 : ' 

: • • ' ' • 

i*" , . • • ' • - - • ' * - X ' } " ? 

•" . ; . / ■ > i. ; - - - ' ‘ ‘ 

. . - • • 

; , , .. . "... » • * ' *" 4 " 

, . ■ i ZZ . r 

.-i V ' -• T> - 

. ■ ■ •• • 

.. . r • h -fgi-?. : •• ‘V vj -r :-L : j- "J*i - ; *-• - v ' 

... . •• i ■■■■'-•, ■ :J X - 

‘ ' - -■ • 

i XL y ■ ' . ' ■ 

• ' 

' • -. >’< ,,.. • . . • • • • i' 

. * • :? - • 

\ • t •: ;■ ■ -v • • •• 1 ■ 










- 20 - 


5*6 dm* in diameter and was fruiting heavily. It grows more 
rapidly than the maple end in its earlier stages requires 
muoh nore light* Seedlings are comparatively rare in the 
hemlock forest; when found, they are apt to occur in well- 
lighted windfalls* Sometimes they arc; very numerous on a 
email area in full sunlight• They occur also on rotting logs 
with hemlock and other seedlings, and are apparently free from 
disease. The natural point of regeneration for the apscics 
is in vindfall ureas* Where an area has been slightly burned 
over, the seedlings are sometimes very numerous* At one point, 
where the forest had been cut away, the mature specimens cf 
birch seemed nore prone to rot than the maple, apparently 
suffering from a sudden influx of bright sunlight; in other 
words, maple seems to be u less critical tree in most cf its 
stages, than the birch* The latter is a much less aggressive 
reproducer than the maple, in spite of the fact that it seeds 
mere often* It may and often does become extensiv e in its 
habit (Prothingham 13), producing largo stands of even-aged 
trees, which shows that its seed production has a high enough 
"factor of safety" to be vvell within the limits reouired by 
nature* Besides reproduction by seeds, this species readily 
sprouts from the stump* It seems clear that its relative 
distribution in the hemlock: climax is net based cn the perform¬ 
ance of its seeds, but on its less tolerance for shade con- 




. 

' •• ■ 

• • 

- ; * 

' : : . • 

. <y- x 

. 















21 - 


ditions than the maple and hemlock* 

omm SPiiCIKS OF TRKi$8 III TKK IDmOCK: FOREST. - Several 
other tree species occur, hut they are of less Importance eco¬ 
logically than those mentioned. One of those of occasional occur¬ 
rence is basswood ( Tili a amo r lean a L«). It gets to be a large tree, 
with a clear hole nearly up to the forest crown. Seedlings were 
frequently found, having a distinctly prostrate habit, the leaves 
becoming very large in the shade. (Thuja occidental is L. (arbor 

vitas) occurs in low spots but is not a tree of general die- 

% 

tribution. As a forest tree it often becomes very large. Its 
presence along the shore line will be discussed litter. Pinus 
St rob us L. (white pine) is occasionally found as a very large 
tree, towering above the rest of the forest. My observations 
seamed to indicate that where one was found, several others were 
likely to occur in the some neighborhood. Abies balSamoa (L.) 

Mill, (balsam) is not common. It is rarely found as a mature 
tree in the hemlock forest, though seedlings are often frequent 
in windfall openings, and occasionally colonies of young trees 
are found in like situations. Whether this species will mature 
in competition with others evidently depends on the size of the 
forest opening; in most cases it is suppressed by the more shade- 
tclerant trees, \7hen it occurs as a mature tree in the forest, 
it is safe to infer that the opening was well lighted for a 
considerable length of time. Its beha\ r ior in this respect bears 















. ■ t v' • ' • • 

. - . ... ... V . . 

‘ - ’ ■ 

. 7 . • • • Q ■ •• • ■ 

. ■ • • L . - 

, • • ' 

. 

. : . ? . • 

.r ~ ■ • • i 

. -v ;; 

. 

■1*6 l • - *>V 

. '• •. • / 1 ; : i i 

♦ ... —..... t.... •■*--- 

. 

, ■ - ■ i ■ - 

■ . . - : ■ » • . • : 
•. • . ■ i\ - ; •, .... - ■ :. . : .; j 

' • ■ ' ' .■ : •: 

. * 

. : : 

, ' ; * ! ' - f * s .. .- • . : • -• *• v . 

.- • .. . -- : i 

- ; -: -. • • , . • ...'•>7 - • ■ ’ • / 



















out the findings of Cooper (Z>) on Isle Royal 0 , where he showed 
that the birth-rate of this species Is balanced by a high rate 

of mortality when in competition with certain other species. 

> 

Other tree species occasionally found in the hemlook 
climax are 2i eea canadensis (Mill.) BSP (white spruce), Quorcus 
rubra L. (red oak) , Fraxinua amerlcana L. (white ash) , and 
0atrya virgin 1 ana (Mill.) K. Jfoch (hop hornbeam). 

B. QUADRAT STUD IBS. 

% 

This method was found useful in connection with the 
study of forest regeneration, and the distribution of the 
principal species. 7/hare it became necessary to determine the 
average ages of the trees, this v?us done by means of tables 
prepared by Frothinghan (IS). The trees were too large to maxe 
felling practicable for this work. Besides the quadrat studies 
every other means that suggested itself was used for gaining 
a knowledge of the dynamics of the forest. The quadrats were 
10 ns. square. 

QUADRAT 1 (fig. II). - This quadrat shows 
the distribution of trees in the typical hemlock climax shown 
in fig. 6. It represents a condition of mature growth. Most 
of the trees here stand at w average distance of from £ to 3 
m. It is noticeable, hovievur, that practically half of this 
quadrat is occupied by a giant hemlock 300 years old, -whose 





































































































■ 

















Fig. 11. - Quadrat 1 (see fig. 
6 for locution): the numerals indi¬ 
cate the approximate ages of the 


treos: the quadrat is 10 m* square. 

















- - 


































- 














-23- 


sjajiere of influence lias undoubtedly extended much further 
than the younger trees. The f or oat floor here was free of 
large shrubs; of small woody plants, 60 specimens of Rubus 
Parvlflorus wore counted, 14 of Lonlcera canadensis and at 
least 30u seedlings of Acer saccharum . The most conspicuous 
herbaceous plant was Aralia nudicaulis . Other herbaceous 
plants noted were Pliego p tor is Dryopteris , Cllntonia boreal is , 
Galium trifloruia , Mitch el la repons . I it ell a nuda . Cornus 
canadenais . and Dycopodium annotlnun . In fact, both the woody 
and herbaceous vegetation were typical of a well-drained 
portion of the dense hemlock forest. 

QUADRAT 2 (fig* 12). - This was taken in 
a windfall. It consists of comparatively young growth. The 
oldest standing specimens consist of a hemlock 130 years old, 
a white spruce 110, and a sugar maple 90 years old; and none 
of these had reached their full growth. The dominating 
influence of this hamlocK is clearly shown in the diagram. 

Its dense spray is more effective in causing suppression than 
that of the maple or even of the white spruce. The best- 
lighted area of the quadrat is occupied by the younger growth, 
nearly one-third of which consists of balsam. The maple, 

100 years old, shown near the top of the quadrat, was broken 
off several feet above the base by a secondary windfall, and 
in falling apparently leveled four other trees as shown. 


















































* 

















. 








' 



























Fsaga. cATiJL de n s/s t-C Acer- Jdcc/idrum as 

Abies baj s a.mea. &b Picea. ca.na.den & is pc. 

Jietula. hjtea. bl Popu)us grandidentata.pg 

Fa.! ten tree. •— 


Fig* 12. - Quadrat 2: taken In a 
windfall area in the hemlock climax 

















- 




► 


: i. . . 










24 — 


consisting of two balsams, a yellow-birch, and a specimen 
of large-toothed aspen (Populua grandidentata ). The last 
three species named are all faeter-grcwing than hemlock or 
maple. Of the 14 trees which are standing, 5 are balsams, 

a hemlocks, Z maples and 1 shite aprftco. The oldest balsam 
is 50 years, and it is certain the other balsams will be 

suppressed, probably before any one of them reaches loO. 
White spruce ( l 3 icea canadensis ) is very rare in the hemlock 
forest, and it is likely that this single specimen will 
eventually disappear before the maturing hemlocks. This 
leaves the struggle between the 5 hemlocks and the 2 maples, 
and typifies the final stage in any windfall. It is vory 
suggestive as to the light it sheds on the ultimate com¬ 
position of the forest at this point. 

Salmonberry and largo seedlings of mountain maple 
and sugar maple formed a low woody growth that acted as a 
screen for the usual herbaceous vegetation. The quadrat 
contained several hundred sugar maple seedlings, the oldest 
being about 5 years. These latter were very much affected 
by anthracnose leaf spot and by an insect disease. Ninety 
hemlock seedlings were counted, mostly growing on rotting 
logs in the shadier part of the quadrat. Large-toothed 
aspen was represented by 15 seedlings; the largest in¬ 
dividuals, though only 3 years old, were twice as tall as 










•• • 



, 

. 


































■ 

























■ 






















26 


tho 5-ycur seedlings of sugar maple* Balsam seedlings wore 
found in the suimier parts of the quadrat, Zb individuals 
being counted* Several species of moss, already mentioned, 
were found on rotting logs in or near this quadrat* They are 
often of considerable ecological importance in the formation 
of seod beds* 

In tho quadrat studies above described, certain 
conclusions in regard to shade tolerance and its effect in 
the distribution of the species, seem inevitable* This will 
bo considered in what follows* 

3. IUITIiiL PHYSICAL FACTORS AND COMPETITION. 

I<; is evident that a great many factors enter in 
to the dynamics of the forest* a few of those have been 
pointed out as thoy affect the life history and occurrence 
of the dominant species of troes* In a consideration of the 
composition of the hemlock climax on the north slopo, two 
questions arise* First, what cutises tho variation in com¬ 
position from tho base of tho elope to tho top of the ridgo, 
a difference in elevation of approximately 300 m.? Second, 
what is the most effective factor governing tho composition at 
any one point? Frothingham has pointed out that there are 
two sets of factors influencing the distribution and dominance 
of trees in tho natural forest, namely, physical , including 
soil, humidity, li^ht, etc. and physiological (biotic) including 

















- 















- 




. 








V 










** * - 













. ■ " • -• . '• 

. • 

. 

, 

:: 

. . 


/ 
















. 




- 26 - 


aggressiveness in reproduction, tolerance of shade, rate 
of growth, form, size, longevity, and resistance to injury 
and disease. The first question seems to he answered hy a 
consideration of the physical factors of moisture and light. 
Soil evidently has little to do with it; if all the hem¬ 
locks were removed from the north slope, maple oould easily 
take possession, as is evident from its regeneration in 
windfalls, and its prominence in the ranges further south. 
Hemlock, rather than maple, is thus the critical tree on the 
north side of the first range. This species is known to 
prefer cool, moist slopes, where the drainage is f&ir. Good 
drainage, however, may he left out of consideration here, 
as it occurs on the ranges farther south where hemlock is 
not prominent. The greatest humidity lies low along the lake 
shore. Here dense fogs are frequent even in the earlier part 
of the growing season. The smaller ratio of humidity at 
the higher elevations allows a corresponding increase in the 
intensity of the light near the top of the ridge. As before 
noted, hemlock is known to he very sensitive in its response 
to light; it is also known to he more shade tolerant than 
maple. Thus it seems clear that the dominance of hemlock 
at lower elevations on the north slope, and its absence as 
a dense stand on higher elevations and on the ranges further 
south, is correlated with the physical factors of moisture 


, 


. 

- 

. ... . ... 1 

. 

. 

















-27- 


and light. 

The answer to the second question involves 
the consideration of the relative physiological response 
of other species, especially maple and yellow birch, to the 
conditions imposed by the dominant hemlock. Hemlock and 
sugar maple, are the most conspicuous examples in the lake 
Region of what Fro thing ham calls intensive reproducers, 
i.e., species which are more aggressive inside than outside 
the forest. The effective aggressiveness of each species 
i3 due to a oonbination of factors. Both species, when 
growing under forest conditions, are likely to have a 
suppressed period of growth for at least the first 50 years. 
Quadrat studies show a great variation in age of individ¬ 
uals, even among the adult trees forming the forest crown, 
mature trees varying from 100 to 300 years or more. One 
hemlock, measuring about 1 m. in diameter, was estimated 
at over 400 years. The greatest tolerance of maple, how¬ 
ever, seems to be in the seedling stage, quadrat studies 
often showing hundreds of seedlings in the dense shade of 
the hemlocks. On the other hand, the seedlings of hemlock 
are rather critical in their light requirements, being 
killed by too much or too little shade. In general, they 
grow more abundantly in the more open part of the forest, 
but not necessarily in a windfall. 




- 







. 




. 

• . - : t ' 

- 

- >>v : .. . 

• l 

« 

, 

■ ; ... ; . . 

• l •' - ai 

■ 

. . . 

* . . • ; 'l 

♦ ’ 





4. EQUILIBRIUM AT ARY POINT. 

Though the different tree species vary widely 
as to their relative production of seeds and seedlings, it 
seems certain that all are productive enough to be well 
within the limits required by nature. It has been pointed 
out by various observers that the "factor of safety” in 
seed and seedling production is very large and that there 
is an enormous wastage In all cases. While this larger seed 
production may be important on denuded areas, it seems clear 
that it has little to do with the relative number of in¬ 
dividuals of different species, where the dominant species 
are intensive, and where a balance has long been reached 
and maintained. This balance is changed little if any by 
excessive seed production of any species. It is conditioned 
by something more invariable than seed production. The true 
explanation seems to be the relative tolerance of the species 
for each other under the conditions imposed by the physical 
factors at that point. For example, the population of the 
yellow birch, which forms approximately 5^ of the total 
tree population half way up the north slope, is a measure 
of its relative response to the conditions imposed by 
the hemlock and maple. Since the equilibrium of the 
forest represents the result of the effective response of 
each species, the balance may be shown diagrammatically as 


















. 







































. 









. 


















♦ » . .< 


. . 

, 

* 

. 









hemlock 
magpie 
yellow birch 
a.11 other tree species 



Fig* 13.*- Vector diagrams, illustrating 
approximate equilibrium (in number of individ¬ 
uals) at two points on the north slope of the 
first range: the uppor figure illustrates the 
conditions halfway up tho slope; the lower 
figure shows conditions of balance near the 
top; hemlock has been nearly replaced by maple; 
CD is represented largely by busBv/ood and iron- 


wood 




























































. 

^ ^ x r 





























in fig. 13* The vectors DA, AB, and BC # (upper figure) , 
illustrate the effective response of the three principal 
species somewhere up the north slope. Evidently the 
magnitude of the vectors does not correspond to the number 
of individuals of each species; in other words, while 
population may indicate response, it is not a measure of 
it. The vector CD indicates the effective control of all 
other species. The lower figure illustrates the conditions 
of balance near the top of the ridge. If any one species 
were eliminated from the forest, it would soon come back 
in approximately the some proportion at any point. 

C. Successions leading to the hemlock climax. 

1. Primary successions. 

The primary successions leading to the 
hemlock climax may be seen along the shore of Lake Superior, 
at the foot of the first range. The pioneer stages are 
present in most cases, but the transition is often rather 
abrupt. Lack of well marked zonation is probably due to 
the severe conditions along the shore. 

a. Physiographic influences. 

The development of the shore line is 
correlated with the post-glacial history of the Lake Superior 
region. On account of the gradual withdrawal of the lake. 


* 


. 

* 

. 


* ' 

• ; * 

Ki* 


- 





L - - -- J 


Fig* 14* - Kooky shore a few miles west of Union Buy; 
shows sandstone beds dipping toward the north; the edges 
of the tilted strata off shore form a rocky terrace, break¬ 
ing more or less the foroo of tho waves; vegetation roudily 
establishes itsolf in tho joint und bedding pianos, as 
shown; white coating on the rock surface is Farneliu luctoa » 




































































. 

. X.. . 

* 














-30- 


more and more of the north slope of the first range has 
been uncovered, This has probably been counterbalanoed 
by erosion, and by the sinking of the ooast in this region, 
which is believed to be taking place (l). 

The rock shore is the predominant type. Where it is 
gravelly or sandy, a little investigation shows that the 
rook is not far underneath. The exposed rock is largely 
red sandstone, dipping everywhere at an angle, as shown 
in fig. 14. In places conglomerate is exposed and loose 
boulders along the shore are frequent. The ?/idth of the 
rock beach varies from 15 to 45 m. Sandy or gravelly 
beaches in more or less protected places may be narrower 
than this, so that the forest comes comparatively close to 
the water, as shown in fig. 15, which shows a narrow gravel 
beach. 

There is such a variation in the slope and character 
of the rocky shore that it is difficult to divide it into 
any definite zones in accordance with the ecological faotors 
influencing plant life. Its lower portion, being always 
subject to wave action, during both summer and winter, is 
devoid of plant life, exoept in sheltered corners of the 
rooks, which escape the direct pounding of the water. The 
lower limit of plant life is marked, roughly, by the maxi¬ 
mum height of the waves in summer. The winter waves and 


* 


. 

* 

. 

. 

- • ; ■ ■ ■ .. . ' . 

. . 

. 

■* 

... 


► • 


t ... 

' 

* - 




Fig. 15. - A narrow shingle beaoh, in which the forest 
comes unusually close to the water’s edge, being protected 
from the winter storms by the lodge of rod, off shore; note 
zono of white birch and arbor vitae lining the shore at this 
point, bordered by salmon berry and Cornus altorn!foil- ; 
Bcmisetum arvonse growing in tho shingle. 





















. 














* 








*©i" « it " f ) 










-31- 


ioo usually roach much higher than this, and thus mark out 
the upper limits of u zone in which only tho hardiest per¬ 
ennials are able to survive. 

b* The shoro successions. 

Since the surface of tho lake has 
boon at tho present level for a long period of time, the 
distribution of the pioneer associations at any point along 
tho shoro has reached a balance which will remain practically 
the same so long as the climatic, ecological and historical 
factors remain unchanged* In other words, it is probably 
incorrect to say that active invasion or retrogression is 
taking place at the present time, even admitting the slight 
changes in coast line, due to subsidence or erosion. 

The pioneer associations along the shore are composed 
of crevice plants, of lichens and of mosses. On account of 
the frugraontal nature of the rooks, crevice plants appear 
to be tho moot important pioneers; most of them are per¬ 
ennials. The seeds lodge in the moist cracks of joint and 
bedding planes, and germinate even where little or no soil 
is present. Gradually the seedling intercepts enough soil 
for tho establishment of a firm root system, and then is 
able to persist for many years, and spread by means of 
offshoots. Two of the commonest and hardiest species in 
tliio connection are Juncus Dudley! W iegand and Dos champ si a 


« 




















. " ' r ■ ■ ' • • 


















■ 




















































. ■ 

















































Fig. 16. - Shows a wall of conglomerate paralleling the 
shore, and forming a protective barrier to the forest be¬ 
hind it: oonifers and aspens growing under the xerophytlc 
conditions at the top; the conifers include a small white 
pino fin the backgroundj, small specimens of white spruce, 
balsam, ana arbor vitao, all growing in the crevices of 



tiio rod.. 





Fig. 17. - Shows Deooharapsia oaespltosa and ^stor 
Faxoni growing in a typioul situation along the shore: 
note dip of the strata, and fragmental character of the 
rock* 










-32- 


oaespitosa (L.) Beauv. (huirgrass). The former was found 
growing within 3 dm. of the water; the latter is undoubtedly 
the commonest grass growing in the crevioes of the shore 
rooks. 

Pig. 14 represents a typical situation for crevice 
vegetation. Such a habitat enables even woody plants to 
come in very early. In the foreground is shown a large 
specimen of ninebark ( Physooarpus opulifolius ) and in the 
background a small speciman of mountain ash ( :pyr us sitchensis j♦ 
The former has assumed more or less of the krummholz form of 
growth, especially on the lake or windward side; its habit 
of growth thus makes it more efficient as a conserver of 
soil and moisture. 

The rate of succession along the outer shore is evi¬ 
dently not to be measured by the character of the plant life, 
the highest forms being found with the lowest. As before 
indicated, this rate is exceedingly slow, due to the severity 
of the situation. In spite of this, a large number of species 
are found. One group may be olassod as typical crevice plants. 
Among these, besides those mentioned, are Campanula rotund! - 
folia L. (bluebell), Aster Faxoni Porter, Soneoio Balsamitae 
Muhl. (groundsel), Fragaria virgin!ana Duchesne (strawberry), 
Achillea Millefolium L. (yarrow), Bquisetum arvense L. (horse¬ 


tail ). 





































- 






..... -■ 

- • J 




. 


... • - - ;J ■ ■' • 

■ 




- ■ . -■ ■ • 1 - • ■■ ■ " 

• . ■ 

, - ■ : • " 

, 

- 

. . - ** 

. 

■ M ■ : - ’ . 

. .U -1 

































Fig. 18. - Hocii surface well above the wash of the waves: 
the cruatose lichen is Parnelia lactea ; the mose (dar£ patches) 
Grirsnlu qpocarpa ; Polypodium vulgare in crevices near the top 


of the boulder 

























































































" 


































* u i 

































In the outer portion of the shore line, at least,shrubs 
often occupy the most exposed situations. The typioal species 
nre Physooarpus opulifolius (L.) Maxim, (ninebark), Rosa 
acicularis Lindl. var. Bourgeauiana Crepin (wild rose), Salix 
petiolaris Sm., and Cornus stolonifera Michx. f. fred-osier 
dogwood). The seedlings of Populus tremuloides often accompany 
the willows. Along the inner portion of the shore, tree seed¬ 
lings are frequent, the commonest being those of Thuja occi ¬ 
dental is L. Here the usual successions occur, with lichens 
and mosses as pioneers. With a few exceptions, they are well 
above the wash of the winter wavos. The wash of the higher 
water can often be very accurately traced on large isolated 
boulders of conglomerate. This material, on account of its 
differential weathering, supports a richer flora of lichens 
and mosses than the sandstone, and the transition from washed 
to unwashed surface often appears rather abrupt. 

Several species of lichen and moss occur in the severest 
situations. The pioneer crustose lichen appears to be Rhizo - 
oarpon petraeum (Wulf• ) Koerb. This form persists often under 
the lash of the winter waves. Other crustose forms common on 
the rooks further back are Plaoodium aurellium (Hoffm.) Tuck, 
and Lecanora oinera afL.) Sommerf. A few species of moss, 
such as Ceratodon purpureus (L.) Brid., Leptobryum pyriforme 
(L.) Wils. and Funaria hygrometrioa (1. ) Sibth., occur in 






























. ' . 

• • : . : • ... . . ‘ 1 

.. .■ . . • - • ’ .... J .... 

...... 

* 

. . ' - • : * - 
- 0 . ' : 


. . . - - • - 


■ ‘ • 

< . X i: v '*.'?■ ■- ■ ' ■ 

■■ '> : •• 

■ . . \ . . . : . ' 

• • • . • ■ •• •• • : ■- 

* 

; 

,iv;o"' / • ?■*'■ % l . . - 

. 












1 - .V. 


. • ‘ 

: . . ; . 





































1 


u 



■rJ 



Pig* ly* - Shows the roots of vihite pine running for 
several meters along the surface and finally acting as an 
agent of rock displacement: the roots on the far side of 
the tree are covered hy a mat of Arctoataphylos Uvu-ursi ; 
small red pine and aspens bordering the shore in the back¬ 
ground. 












































































































































































































































































































































































_J 


Pig* 20- - A broad type of ehingle beach, devoid of 
vegetation on account of the wash of the winter waves* 





































exposed crevices* In some cases they undoubtedly Jiave the 
way for higher plants. Further Inshore various foliose and 
fruticose lichens and mat-forming mosses form a definite 
stage of the rock succession. Among these may be mentioned 
Grimmia apocarpa (I.) Hedw., Amblystegium varium (Kedw.) 
Lindb., Btiota amplissima (Scop.) Mass*, Panne li a conspersa 
(Ehrh.) Ach., StereE7caul on paschale (L.) Hoffta. and various, 
species of Cladonia, 

Following the mosses and lichens one often finds the 
bearberry ( arotostaphylos Uva-ursi fL*) Spreng,) as a pioneer 
mat former. With the accumulation of more soil, shrubby 
species become more abundant. Besides those mentioned, the 
following occur:- Diorvilla Ionicera Mill, (bush honeysuckle), 
Amelanohier canadensis fL.) Medic, (shad bush), Oornus alter - 
nifolia L. f. and Rub us parviflorus IJutt. (salmon berry). 

In the development of this succession finally come 
the trees, their roots sometime spreading 3 - 10 m. before 
finding.a suitable crevice for anchorage (fig. 19). Roots 
of this kind.form an important barrier for holding back soil 
washed from above. The fallen trunks also assist in the same 
manner, as well as finally furnishing additional humus by 
their decay. 

-Types of shere- 

The character of the shore vegetation is largely in- 

































f *. .. ;t _ ‘ X ■: l.* ■ i' • :0 

- . V .• J . ■' * 

: -v. . *:.l 

. 

V . . ... . • ^ ' .... -- — 

, . * _ • • : 





- - • * ' 

. 








..I- * .... • v :C 1 


• »• ' - • T ‘ I 

. ■ .i ~ ■ 1 * • ° * 

• i t 1 ' 

. ' , . _ • * ... . 



. 












. 




















c 


Pig. 21. - Types of shore line; see text. 













































































' - ; * i . 

































-35- 


fluencQd by variations in physiography. This includes sub¬ 
merged ledges of rook, shore, cliff3, coves and the accumula-r 
tion of shingle barriers. Submerged ledges, breaking the 
effect of the waves, and coves affording protected areas, are 
both factors in extending the forested area closer to the 
water's edge. The effect of these two influences may be 
seen in fig. 15. 

It seemed possible to classify the shore into 
three general types, as shown in fig. 21. Fig* A shows a 
type in which the surface immediately back of the shore line 
is low. It often represents the mouth of a gully, and possibly 
of a drowned river (see Ruthven (23) p. 25). The area is 
swampy, usually being occupied by large specimens of Thuja 
ocoidentalis and Fraxinus nigra . It is sometimes separated 
from the immediate shore line by a narrow zone of shingle 
and driftwood. Back of the area, there is often an abrupt 
rise of from 6 to 10 m. to the typical hemlock forest. 

In B f the hemlock forest extends practically 
up to th 3 shore line, though there is always a fringe of other 
species on the iimiedi ate outskirts, the commonest being arbor 
vitae and white biroh. Other species occurring are Abies 
balsamea , Acer saooharum and Acer spioatum . Stages inter¬ 
mediate between A and B occur. 


C represents the conditions whene the shore line 












. , • • i - ■ 1 

. 

, . ’ V . 

*• • 




■ 

- ’ • • . ’ , . 

- 

. ‘ 

l . ; 

' • . . - ' ■ ‘ . . - \ _ 

! - ' > , . . 

> • ' • . •: ..; ; 
V ' ... , 

• ‘ - • > - ■ . . . j . • 





















-36- 


is bordered by a rocky cliff. In this case the area above 
is often forested to the very edge of the cliff. On account 
of the dip of the strata, such areas are so well drained that 
the vegetation becomes xerophytic in character. This was 
found to bo true even where the soil was 3 dra. deep as was 
observed at one point. At this point the ridge had once been 
covered by a growth of pine, which had been blown dawn, and 
was being followed by a growth of white birch, aspen and 
balsam, the two formwr being on the lake side, being better 
able to adapt themselves to the unusually severe wind con- 

f 

ditions. 


2. Secondary successions in the hemlock climax. 

In the latter part of the summer of 1919, 
an extensive fire swept over a portion of the north range, 
destroying several square miles of virgin hemlock forest. 

This fire extended as far east as the range line between town¬ 
ships 42 and 43. The conffers were killed outright, though 
many dead trunks were left standing (fig. 22). It was very 
evident that the deciduous trees, including the sugar maple 
and especially basswood, were more resi stant to the effects 
of the fire than the conifers. This was especially trtioeable 
in the zone between the burned and unburned areas, where the 
trees were singed. Fig. 22 shows how thoroughly the humus 



. i ; . 

i 

* - 

. . , • t • ; * ;■:* •• " v r. 

• ' ‘ ■ * 

• r - 

- 

i 









• .*• 

; . • V ~- 

• '• - 

- . 

. - - • . 

e - ; 

t ' • . v . - 

.. : ... . j* . - 

. . - 







Pig. 22« - A "bum” in the hemlock forest three year a 
after the fire: note angular character of the sandstone 
fragments underlying the forest floor, the humus being com¬ 
pletely destroyed; north slope of first range looking west. 

























































. . . ■ 






















37- 


w&e burned off, exposing what appears to be ordinary talus 
material, composed of angular* unwashed fragments of sand¬ 
stone, mostly 1-3 dm. in diameter. 

"Burn" associations had started over the entire area, 
being further advanced at some points than at others. She 
commonest herbaceous pioneers consisted of Krigoron canadensis 
L. (horseweod), JBpiloblum angustlfollun L. fprroat willow-herb , 

Aster raacrophyllu s 1., .uraliu hispid a Vent, (bristly sarsa- 

\ 

parilla), and Holygonun Pour-la si 1 Greene. Amongst the shrubby 
species coming in next tho following were noted:- Hub us purvi - 
florus (s-lmon berryJ, hunbueus racemose L. (red-borried eldor), 
Piervillu henioera Mill* (bush honeysuckle), Rhus typhina L. 
(staghorn sumac), and Kuhns ldaous X,. vur* aouleutlsslmua ( C. 
a. Mey.) Hegel & Tiling. Tliese are followed by ? run as p pansy 1 - 
vanica I». f., (wild red cherry), ^ cor spicatun Lam. (mountain 
maple), seedling aspens and occasional seedlings of sugar 
rauplo ( iicer Bacoharum ). Hemlock seedlings undoubtedly come in 
at a later stage, finally displacing the maple. One of the 
most noticeable elements of this secondary succession is Rubus 
parviflorus . The plant spreads rapidly over large areas by 
stems just below the surface, these stems sometimes being 
several meters long. The foliage forme a "leaf mosaic n which 
reduces the light to such an extent thut shade-tolerant speci os 
are able to make on early start, thus probably hastening the 












































• ' . , • 

l ■ . 

- 



. 

-.-I.- - • ■ 

■ 4 i- 



\ l ’ - •: 






* 

* 







































?i£. 23 • - Quadrat 3. This quadrat 
represents a stand of trees in a foroat of 
almost pure maple; it was taicen in sqc»14, 
about 1U0 m* from the summit of the ridge 
(see fig* 7)* 


















- .• .T. 


'''I 









• - * 





-38- 


climax stage. 


II. THE MaPLE CLIML. 

This is the formation associated with vegetation- 
al development at the top of tho first range and over the 
ranges further south. Its mature form may be seen 100 m. south 
of the summit of the range (fig. 8). Here a 10 m. quadrat 
was laid out (fig. £3). It represents a stand of almost pure 
maple. The larger trees averaged about 4 m. apart, the forest 
canopy being rather dense for maple. The uniformity in the 
ages of several of the younger trees marked them out as the 
survivors of a single generation of seedlings. In fact, the 
presence of several dead saplings varying from 30 to 40 years 
suggested that these trees had already reached a critical 
period in their development. Thrifty specimens of Tilia 
and Ostrya were found just outside the limits of the quadrat. 
The soil at this point was a rich leaf mold of medium acidity. 
It was not deep, as indicated by the root systems of fallen 
trees, exposing the bare rock. Though the forest floor was 
comparatively open, immature shrubby vegetation was repre¬ 
sented by specimens of Kubus parviflorus and Sanbuous race - 
mo sa . The latter species gets to bo vayy large and rampant 
in maple windfalls, dominating the ground cover. The follow¬ 
ing are typical herbaceous species:- ^spidium spinulosum 













- v ^ .. 







... .. 

- . • • -• . . ■ . . - ; 

• V. J 

. • 

- • • • • z -.j ; . 

' •• •'< • • \ • : 

t 

. 

■ ; 

\ }i- i „ - v.- i 

’ • ' • - • ; - 1 :.v; ; . ' • 

<- $ ' . • •; s r 

' * • 



. N ■ v * 

• • • - J - ‘ • i 

.■ •- j\: j •_ *. •; 








-39- 


(0. F. Mtillar ) Sw. vur. intermedium (Muhl.) D. C. Eaton, 
Phogopteris Dryopteris (L. ) Pee (oak fern), Afliantum pedatum 
L. (maidenhair), Botrychium vigfginianum (L.) Sw. (rattle¬ 
snake fern), Hystrix patula Moenoh. (hottle-Brush grass). 

Hilium effusum L. (millet grass), Solidago latlfolia L. 
(broad-leaved golderirod), Kibes Gynosbatl L. (wild goosfebrryy), 
Smilaoina raoemosa (L.) Desf. (false spikenard), Actaea alba 
(I*) Mill, (white baneberry), Viola canadensis , L., Sanguinaria 
canadensis L. (bloodroot), Aralia nudicaulis L. (wild sarsa¬ 
parilla), Polygonatum biflorum (Walt.) Ell* (true Soloman*s 
seal), and Galium triflorurn Miohx. (bedstraw). The last-named 
species is one of the commonest of the smaller groxmd covers* 

The maple climax, as above described, occupies 
a comparatively narrow zone on the north side of the first 
range. As will be shown later its development on the south 
side is as yet in the early stages, this development being 
closely related to the physiographic foatures of the range 
and the adjoining valley of Carp River. 

A. General physiographic features. 

That the top of the first range still holds out 
against the mesophytic forest is undoubtedly due to the 
peculiar topography of this range. As is evident from fig. 3, 
this topography is associated with the geological formation 



































,• . . . . 

' - . 

, - • . . 

.. , . 

. - ' • _ . ■ _ 

: . . . 

... 

• - , . . 




J.-si ox .... - _ _ . ' . 

- ■ • : . “ . . 


/ , , 

: . ' . : . : 


•• ■ .. . 

. . . ■■ 

■ 

• • ■ l ; : : ’ ■ . 



► 






. . .. Xu-.. 

- ; • ' '• • . ■ - , ; * v ■ . 

Gi . . i . . 'X' • . ; 






































Pig* 24* - Cliff and talus slope, first range: view 
from a point just east of Carp Lake, looking north; the 
cliff at this point is about 130 m. abovo the floor of 
Carp River Valley and 240 m* abovo Lake Superior; the 
face of the escarpment is approximately 65 m* high at this 
point; note fringe of forest between talus slope and river 
valley* 
















3 1 f , .-4 »• Z'.ti , l 








* 









. 

































Pig. 25. - View of cliff in section 15 f T. 51 K. R. 43 W., 
looicing east: in the foreground are shown tho last stages of 
the cliff, preceding the formation of a B&&dle; in places the 
soil has accumulated on the bare roc£; note xerophytic char¬ 
acter of the vegetation. 

























. 










. 









. . • • 




























•40 


Of Carp Lake, which was once much larger than at present. 
f rha dip oT the strata toward the north has created a great 
cliff or escarpment, which is continually weathering away, 
producing a talus slope at its foot (fig. 24). This cliff 
extends west and west-southwest across T* 51 B. H. 43 V/., 
a distance of about 10 km. I*c varies from point to point 
alo r the range as to elevation of summit, height of escarp¬ 
ment and width of talus slope. At. one point opposite Carp 
lake the talus descends into the luko; hut at most points 
there is a fringe of forest between the foot of the talus 
and flood plain of the river, as shown in fig. 24. In sec. 

14, there is a depression in the cliff where the escarpment 
has entirely disappeared leaving a saddle across the range. 

The same thing, though less marked, occurs about a mile 
west in sec. 15, and in varying degrees at other points along 
the range, making it possible at such places to descend into 
the valley without difficulty. Where a saddle i3 sufficiently 
low, as in sec. 14, the talus is almost entirely covered by 
soil washed from above, and the fringe of forest, from below 
may extend clear across the depression. In sec. 15. (fig. 

25} this process has not gone so far. There is still a rock 
faco varying from 3 to 5 m. high. The relation between the 
various physiographic features as thoy appear at different 
points along the range is shown in fig. 26. 





















. 


















. 























. 













[**4|j I . . is 


r; ; #» "fc . . 

I ' 








-J 


Pig. h6. - Typical cross-sections at various points 


through the auranit of tho first range 










-41 


A represents a stage of the cliff found opposite 
Carp Lake in sec* 22. Here the escarpment is high and the 
talus slope dips into the lake. At this point the trap and 
sandstone portions of the cliff can readily ho di stinguished. 
The trap is superimposed upon the sandstone, and has under¬ 
gone a greater disintegration, forming a ledge as shown. 

B and 0 typify ordinary conditions whore the escarpment is 
high and the talus slope from £00 - 300 m. wide, bordered by 
a more or less mesophytic forest at the foot. At 3) is shown 
a stage where the top has been rounded off to such an extent 
that xerophytic tree species, such as red and white pine, 
are able to gain a footing. The former is usually more 
abundant under the brow of the cliff, where it is more or 
less sheltered. The latter is found in the more exposed 
situations, being the first to creep over the top when 
the conditions become favorable. Stages B, C, and D may 
all be seen in section 14. IS and F represent stages at a 
low point in the range, such as is shown in fig. 25, preced¬ 
ing the formation of a saddle. Here tho talus slope is 
much reduced, the forest pushing well up toward the summit, 

even though the latter may still remain xerophytic. 

0 

B- Successional relations 

I. Xeraroh successions on the first range. 
m ecological survey of the vegetation 


' 3 - 

; • 

- ' 


; , : . ; '• . " ‘ ’ 

t : • ■- < ■■■-'" ’■ 

# ■ - . _ - . : •; ‘ 1 - - - ' • ■ 

- 5 : • - 

; ; . ■ . . -- • 

• • .. , • - • - *" ' 

. ' ' ‘ T • ' * . 

■ . • : • 

•- :: : • - * ■ 





Pig. £7. - Limit of forotst growth on summit of ridge, 
looking oast. The prevailing direction of the wind is from 
the southwest; this is more or less evident from the general 
direction of the branches in the small pines shown; clump 
of small red pines in background (to left); basrberry mat 
on rock in foreground. 





































-42 


involves an examination of the environmental factors and 
plant successions (1) at the summit (2) along the escarp¬ 
ment (3) on the talus slope (4) below the talus slope* 

(l) Summit of the range. 

fa) Ecological factors. In general, 
the forested area of the north slope may fall short of 
reaching the crest of the ridge, as shown in fig. 26, E, 
or may reach slightly over the summit, as at F. From 
this point to the brink of the precipitous cliff, which 
averages from 20 - 40 m., there is usually a large amount 
of bare rock surface. Where the soil has accumulated, it 
is of very slight depth. There seem to be two principal 
reasons for this condition, both being due to the presence 
of the escarpment; fl) the soil due to rock disintegration 
is washed over the south side of the crest nearly as fast 
as it is formed, (2) the escarpment itself forms an effectual 
barrier to the encroachment of the mesophytic forest below. 
This zone of bare or nearly bare rock surface therefore re¬ 
mains unprotected. Its exposed situation makes it especially 
susceptible to the dynamics of weathering, including the 
frost of winter, the heat of summer, full exposure to rain 
and to all winds from the south. A portion of the soil 
wafefced over the crest accumulates in a narrow strip along 
the top of the talus slope. The rest is gradually washed 








. 











. t 

. 

. 

■ 

■ . 

* 

. 




. 




Fig. 28- - A portion of tho summit, looking oust: Carp 
River in the valley below fat right); small red pines and 
stunted aspens to tho left, back of which a transition zone 
occurs as shown in fig- 32, leading to the maple climax of 
tho north slope; note pines growing from crevices in face 
of escarpment. 

















































































































. 








. 






, ■ . : . ✓ 






















down through the talus, finally reaching the forested area 
at its foot. On the other hand, soil found on the north 
crest is soon cheeked in its descent by the forest. A certain 
amount of it collects in depressions and irregularities of the 
rock surface and along the edges of joint planes, affording 
a foothold for crevice plants and matted vegetation. 

(b) The plant associations. 

The pioneer stages at the summit 
consist of lichens and mosses on the bare rock surface, and 
on the ground. Among the commoner crustose lichens appear 
such forms as Lecanora cinerea , Rhizocarpon petraeum and 
PIacodium aurellium . Following these come foliose species, 
Parmelia conspersa (Khrh.) Ach. being the most conspicuous 
and covering a large proportion of the rock surface; Physcia 
obscura (Schaer.) Hyl., Lecanora garovaglii and Gyrophora 
hyperborea Ach. are less common. Where a slight amount of 
soil has accumulated on the rock surfaces, fruticose types 
appear, common species being Cladonia rangiferina (L.) Web., 
Claddmia sylvatica (L.) Hoffm., and Stereocaulon paschale 
(L.) Hoffm. 

Associated with the lichens in the pioneer rock suc¬ 
cessions are moss species, such as Grimmia apooarpa , Poly - 
trichum piliferum Schreb. and Tortella tortuosa (L.) Limpr., 


the two latter being the commonest. One of the early mat 





























. 

... 




, ■ : - 

. 







» 

* 

• * 






, M i . 


. 




























Fig. 2^* - Cioae-up of rock eurface, crest of ridgo: 
in the foreground, Juniperua communis var. deprea8a , Danthonla 
aplcata . Antennuria noodiolca , Potontillu trldentata . Poly ¬ 
gonum Dougiaeii (lower right), and Parmeli a conapersa , the 
dominant lichen; Solid ago randii var. nentlcola in the back¬ 
ground. 



























































































formers is Solaginalla rpuestris (L.) Spring., often Cover¬ 
ing large areas on the rook surface. It is not uncommon 
to find superposed upon this mat the two common mosses 
already mentioned. The Selaginella mat becomes nearly 1 
dm. thick in plaoes, living plants growing on the dead 
mat of former generations. This paves the way for her^ 
baceous plants, such as Danthonia 3picata (L.) Beauv. (wild 
oat grass), Potenti 11a tridentata Ait. (three-tootiled 
cinquefoil), and even for woody species, such as the bear- 
berry ( Arctostaphylos Uva-ursi (L.) Spreng.) and stunted 
specimens, (2 - 4 dm. high), of staghorn sumac ( Khus typhina 
L.). The roots of the latter creep over the rock surface 
for several decimeters until finally they may become anchored 
in a crevice, arctostaphylos is especially well adapted 
to the severe conditions found on these rock surfaces. Often 
it occurs in large patches, thus aiding in the retention of 
more soil and the conservation of soil moisture. Large 
angular depressions in the rook surface may occasionally 
be found where enough moisture is retained to support even 
shrubby growth without being definitely anchored in a crevice. 
Such a case was illustrated by a low specimen ( 2 - 3 dm. 
high) of Hew Jersey tea ( Oeanothus am eric anus L. ) which had 
adapted itself completely to the shape of the depression, 
but could be pulled out bodily as a dense mat. 














■: 0 ,. • f :l ... .... - ' 

. .. 1 • 




. 

• - . . . 

t . . - . . ■ 

S . i: i ■( * *' - ' ,r ‘' 

. , at ■» — 

* 

» ■ .. 

•' « 






















- 45 - 


Muoh of the rook at the bare summit is more or less 
porous in texture; rook fragments are numerous but irregular. 
Joint and bedding planes are not as distinctly marked as 
on the face of the escarpment. Whenever a orevice occurs, 
however, soil readily collects, and a number of plants gain 
a footing. The summer flora is practically a xerophytic 
one; the occurrence of certain vernal species, however, 
indicates that during the spring there is a comparatively 
large amount of moisture on the ridge, due in part, pro¬ 
bably, to the melting snow. Of the orevice plants, Danthonia 
spioata , already mentioned, is one of the most important, 
on account of it3 abundance and its densely tufted habit 
of growth. Other noteworthy crevice plants are Solidago 
randii Britton var. montioola Porter, Potentilla tridentata . 
artemisia candata Michx., Woodsia ilvensis (L.) R. Br., 
Campanula rotundifolia L. (harebell), Viola arenaria DC. 

(sand violet), Aquilegia canadensis L. (wild columbine), 
Panicum denauperatum Muhl. and Panicum meridionale Ashe. 

Where a small amount of dry soil has accumulated, the 
following occur: Antennaria neodioica Greene (everlasting), 
Lechea striota Leggett (pinweed), Panicum xanthophysum 
Gray, Satureja vulgaris (L.) Fritsch. (basil), Aralia 
hispida Vent, (bristly sarsaparilla), Apocynum androesi - 


mifolium L. (spreading dog bane). Bpigaea repeps L. (trailing 
















































- 









, ; 

. 

. • • • 

’ c ?• * • 

I •- it ©tfftalQ ^olvc'ic *»ri^O • -~ T ' r '—' •* - : - 

* ■ J „ i. ,l$e£olir $jaa«) 

. _ . ... . '_ 

, 

. '. -- L • 

’ .. 

• . - • • ; , 









































- 46 - 


arbutus), Hieraciuri soabrnii Iliohx* (huwkweed), lip il obi pis 
angnstifoliun L*, ^.ster macro hyllus L., Corydalls semper - 
vlrons (L•} Pers., Oerastlun arvonso L«, Fragaria vosc-> 

L. var. a nor io ana Porter, apd Our ox adust., Boott. 

It will be noted that the above are porronnial species* 
A few annuals occur, such as Silono antlrrhlna L*, (sleepy 
catchfly), KrIgoron canadensis L. (horse-weed), and Poly ¬ 
gonum Pouglasll Greene. These annuals lead a precarious 
existence, as their seeds must, in tho main, bo washed 
over the cliff each year* The distribution of the above 
herbaooous species varies considerably from one point of 
the ridge to another. Their presence results in the 
accumulation of humus, especially in depressions or in 
connection with dead mats of Solaginella* 

Accompanying the herbaceous vegetation are a few 
speoies of low shrubs, the commonest being species of 
blueberry ( Yaceiniun ponnsylvanioura Lam. var. angustl - 
folium (idt«) Gray and Vaooiniuci nigrum Britton). These 
often form largo patches slightly bach of the summit, 
where more soil has accumulated. Other spocios found 
along the summit are:- Juniporus oonmunis L. var. nontana 
Ait., Bosa aclcularis Lindl., Sails humulls Marsh., Dior - 
villa Lonicora Hill*, Shepherdla canadensis fL.) IJutt., 
and stunted specimens of Juneborry ( iimolanohier oana - 



























































. 

























. 




- 


, 1 I 

■ 






















































Fig. 30. - 
(laaplo oliiaax) t 
14, T. 51 ft. ft. 


Transition to mosophytic forest 
top of ridge, at a point in sec. 
43 17.; soo description of quadrat 


4 and 5 










































































- 47 - 


densis (L.) Medic. 

A few dwarfed specimens of white pine ( Pinus Strobus ) 
are scattered along the summit, but the species is much 
more common over the crest of the ridge (fig. 24), where 
it receives more shelter and moisture. The gray pine ( Pinus 
Ban Asians Lamb.) was noticed at only one point. 

The limit of forest growth is bordered by a very dis¬ 
tinct transitional zone all along the summit. The general 
character of this is shown in fig. 28, but it varies a great 
deal in composition at different points of the ridge, ap¬ 
proaching more mesophytic conditions at lower elevations. 
Gnarled and stunted specimens of red oak ( Quercus rubra L.) 
are mingled with aspen ( Populus tremuloides Michx.) and 
white birch ( Betula alba L. var. papyrifera (Marsh.) Spach.), 
the latter sometimes appearing in almost pure stands. 

(c) Quadrat studies. 

A detailed study of the transitional zone was made 
at a point in sec. 14, just west of the saddle (see map). 

This is typical of most of the ridgo. Beginning at the 
area of bare rock surface shown in fig. 29, situated 
approximately 25 ra. bacA from the face of the cliff, a 
series of four quadrats was taken in succession, the last 
being in the mesophytic forest (fig. 50). These quadrats 
were 10 ra. square, making the total width of the transitional 














f . t 

;'j i ■ r t •• 1 : 

•; ItJt c t 

H • » 

. . . * 

. ! .' ... -■it 

, . . . 

> -j i . 

. 

. ■ . • - • 

• - 'i*v 














• 

as 

• 


• 

as 

• 

<Jr 


r 


• 







as 

• 


• 




? r 


as 

• 






as 




• 




• 


as 




as 





• 

• 

• 

a_5 



as 

as 

? r 

• 






dS 

• 






as 






• 






as 



• 






ov 


• 






cLS 


bi 

• 




• 

as 


as 








• 



• 


• 

•s/i 



p r 


l° r 

P r 



• 





• 

p r 


• 



ca 


Pr 


• 

• 


• 



pr 

• 

p r 

-p* 


P r 

ca. 

. * sp 

• 





ca. . 

P r 

• 


Pr 



• 

P r 


• 



• asp 

ca - . 



•r 



Pr 


• 

• 


ca 

• 

P r 


Pr 

Pr 



" ** 


ca 

• 

ca 


rock surface 









__ 





_— 









Acer sa.ccha.rurn as 
Qoercua rubra. <^r 
Bctu I <a_ |utea_ bl 
Ostry*- virgin I a.n <t ov 
Populut t. remu lo'• ole* 


Pinos resjnoja. pr 
Cca.nothuj imcricanos ca. 
Arneld.ncbi'e.r sp a.sp 
5 a. \ ■ x homilis S h 


Pig. 31. 


Quadrata 4 and 3; see 


fig. 


2U and toxt 

































































































. 








































































zone 40 in. at this point. 

QUADRAT 4 (fig. 21) was taken to include a portion 
oi the rock surface (fig. 29 ) f as well as the marginal tree 
growth. Here the soil was thin and dry, the ground sloping 
gently toward the south. Several small red pines ( Pinus 
resinosa ) represented the typical tree growth. They stood 
comparatively close, with small dead ones intermingled, 
amongst the red pines were a few small white pines and 
balsams. Aster macrophyllus L. formed a large proportion 
of the ground cover. Besides this were several other 
speoies already mentioned as typical of exposed portions 
of the ridge, such as Salix humulis , Vacoinium spp., Artemisia 
caudata . etc. 

QUADRAT 5 typified the zone of scrubby red oaks 
(fig. 32), a characteristic belt very often following the 
conifers. The oak growth consisted mostly of sprouts (up 
to 3 m. high) coming from old root crowns in very shallow 
soil. This quadrat came Just north of the crest, so that 
the surface sloped gently towards the north. The conditions, 
however, were still xerophytic, as indicated by the presence 
of such plants as Aralia hispida , Danthonia spioata , and 
large patches of ffunaria hygrometrica . There were also a 
few scattered seedlings of aspen, white birch and sugar 
maple. There were some evidences of burning on this 






























. ■ • : ; ■ J 

I 

. 

. j, . : r.’i', 

....... t . 

* 

. 

. 

. 

- 








* 



, 

' ■ ■- y ' 'i r, ti 

« 
















Pig. 32* - Zone of transitional tree growth at quadrat 
5: note red pines, email red oaks, and aspens; bare rock 
surface in places; the conspicuous grass is Danthonla spieata . 

















\ 


49 


quadrat, so that conditions might not have heon entirely 
typical, Funaria hygrometrioa was found to be very common 
in burned areas over various parts of the region. In 
general the oak sprouts soern to be the ecological equivalent 
of young rod pine. The ground cover was much the sane as 
the preceding quadrat, with the exception of Polygonum dume - 
torum, a very common species along- the edge of the meso- 
phytic forest, 

QUADRAT 6 represents a transitional stage from 
quadrat number 5, in which the oak constituent has reached 
a higher 3tage of development, the individuals attaining 
a height of from 7 - 10 m., with much less sprouting, though 
still indicating somewhat unfavorable conditions. The pre¬ 
sence of red maple and numerous sugar maple in the northern 
half of the quadrat indicated the transition to the meso- 
phytic maple forest. 

QUADRAT 7, The striking feature of this quadrat 

I 

v/as the dominance (in numbers) of sugar maple saplings 
5-10 cm. in diameter. Intermingled with these were well 
developed specimens of red oak (up to 15 m. or more high), 
hop hornbeam ( Ostrya virginiana ) and yellow birch ( Betula 
lutea ). 

Following quadrat 7, the maples gradually in¬ 
crease in size, ofton accompanied by basswood and a thick 
















. 

. ... ' ' • - ‘ 

... 

... 0: J 

aoo :5*0 »dt flair. it .« xtulauia 

■ 

j I : . . • ■ ' 





. 






, 

- *• 


























grcwth of red-berried elder (Sambucus racemosa) t the 


latter disappearing or becoming less frequent in the 
denser shade of the mesophytic forest further down the 
slope. Along the upper limit of the maple forest, it 
is not uncommon to see the flat, upturned root systems 
of trees, especially maples, which have adapted themselves 
to a layer of soil not over 1 dm. thick over the rock 
surface. This area is more or less subject to windfalls, 
apparently not because the velocity of the wind is greater 
here than nearer the summit, but because it forms a 
critical line between the low types of trees which spread 
their roots out through the shallow soil, with crevice 
connections in many oases, and the taller types which owe 
their increased size to a deeper, richer soil, but which 
offer a greater leverage to the force of the wind. 

The above description of the transition from 
rocky summit to mesophytic forest applies in general to 
the higher portions of the range. Variations naturally 
occur, depdnding op the elevation, exposure, local topo¬ 
graphy and depth of soil. 

(2) The escarpment and its associations. 

The height of the rock face or escarp¬ 
ment varies at different points along the range, as shown 
in fig. 24. The upper portion may be vertical or nearly 





































- 

s. r> «; ■ 0 > * 

■ 

. 

, • 




















Pig. 33. - Overhanging ledge of 


cliff shown in fig. 25* £z shows dip of 
the strata (sandstone); various plants 
gain a foothold in the moist crevices 
(see text p.5l). 





— 



























































































so. The lower portion curves around to meet the talus 
slope, which is very steep at the top; or there may "be a 
series of lower escarpments wi th shorter talus slopes be¬ 
tween as shown at the left (fig. 24). Owing to the dip 
of the strata, the face of the cliff is alv;ays very uneven, 
and the seams of the rock, on account of the direction of 
dip, often retain a sufficient degree of moisture to 
support the more xerophytic tree types. The unusual sever¬ 
ity of the situation so far as vegetation is concerned, is 
due to the continual splitting off of rook fragments from 
the parent rock. 

The cliff is often "broken by ledges, due to 
different resistances of the various kind of rock to 
weathering; these may vary in width from a few decimeters 
to several meters, with corresponding accumulations of 
soil. On the vertical rook faces, a few species of lichens 
may be found, such as Locidoa lucida A oh., Gyrophora vellea 
(L.) ach. and Ainphlloma lanuginosum (Hoffm. ) Uyl. The 
vortical face of sandstone represented in A, fig. 26, is 
marked by bands of the yellow lichen, Placodium elegans . 
Where ledges overhang, as shown in fig. 33, the conditions 
are more moist on account of the shade. Amphiloma lanupin- 
osum and the leafy liverwort, Radula complanata , aro usually 


abundant; also various foliose and frutiooso lichens, such 
















. 


- • 





. ■ 


; , ' - ' 


■ 

. ■ 

1 

’ - ' 

. . . ' _ 

... . - »■ f 
j . • C * 































Vig* 34* - Hock ledge on face of escarpment.look¬ 
ing east: in the foreground, two snail white pines and 
small specimens of Prurtua pennsylvanlca . Phus typhlna . 
and Corn us clrcinata ; also Arctostuphylos Uva-ural , 
Artemisia caudata . and Danthonla spicata ; in the back- 
ground, a snail red pine, and loaves of oak ( Ouorcus 
rubra ) showing below; Parmelia conspersa on rock sur¬ 
face above and below; V/ocdsla llvensis and Campanula 
rotundifolla growing from rock crovices fin foreground)* 



























such as Physcia obscura (Schaer.) Hyl., Parmelia caperata 
5 Ach., Puiaullna calicaris (L.) Fr., and Qyrophora vallea 
(L.) Ach* In the crevices of such ledges occur two character¬ 
istic fern species, namely. Polypodium vulgare L* and Woodsia 
ilvensls (L.) R. Br. 

The flora of the exposed ledges is very variable* 

On the smaller, newer lodges, a few lichen epecioa, such as 
Lecidea lactea (Plot.) Sohaer. and Parmolia conspersa (rlhrh.} 

Ach* nay gain a footing* On larger ledges, the higher plants 
are usually well represented, from small herbaceous species 
to trees whose roots are anchored in some of the bigger cre¬ 
vices (fig. 34)* Typical species are shown in the figure* 

Among others nay be mentioned Potentilla tridentata . Panicue; 
xanthophyaum . CeanOthus oner icanus , ??ubus parviflorus . Amel - 
anchier canadensis . Polystichum Lonehitis , Thuja occidentalis . 
and Juniperus co;munfta L* vur. mentana Ait* 

When there is a marked difference in rate of 
weathering between the sandstone and trap, a bread ledge 10 - 
16 m* aoross mey be formed (fig* 26A). On account of the greater 
deposit of soil and consequent storage of moisture, the con¬ 
ditions here are much moro stable* Such an area may develop 
a comparatively thicx stand of pine, thriving under the pro¬ 
tection of the cliff. 


The destiny of the escarpment is the condition seen 





























































. 




. ' ■ Qi , ' . MiSM i 











* 





































































Lt- 






Fig. 36. - View of first range, looking 
14: Carp Kiver and valley to the right; shows 
reduction of escarpment and advance of forest 


east, in sec. 
stage in 
up the slope* 





































































■ 

































































































-63- 


where at present saddles cross the range. Gutting will 
continue at the top and face, and filling will continue 
at the bottom until the lines of cut and fill meet. In¬ 
vasion of mesophytio types will principally be from below, 
the summit holding out longest against the final meso- 

X 

phytic forest. Fig. 35 shows a stage approaching such a 
condition. 

(3) Talus slope. 

In general the width of the talus 
slope depends on the height of the escarpment, especially 
where the latter is not broken by large ledges. When the 
face of the cliff is low, the band of talus is comparative 
ly narrow, for here the rock fragments from above do not 
come in sufficient numbers to prevent invasion of the 

forest below. Where the cliff is high, many of the larger 

, *• 

fsagments may roll 200 or 300 m.,* effectively checking the 
growth of the forest beyond this point. The resulting 
area is desolate in appearance ffig.36), very little 
vegetation gaining a foothold except near the top and 
bottom. 

Where the cliff is principally sandstone, the rock 
fragments are smaller and more flattened than where trap 
predominates. In the former case soil apparently collects 
more quickly and vegetation makes a more rapid invasion. 


. 








' * 

. 

. 

: - : 








, 

• . 

‘ 

. 




. 





Fig- 36. - Bottom of talus immediately west of saddle 
in seo. 14, looking east: angle of slope here is about 30°; 
note line of forest as it creeps over the saddle across the 
low point of the range; the cliff at this point is very high 
and the talus field 200 m- or more in width; shows character¬ 
istic clumping habit of white birch when growing in talus- 



















. 



















-64- 


As pointed out bofor \ there are two points on the talus 
where soil first begins to accumulate, namely, the bottom 
of the slope along tho margin of tho forest and the very 
top - at the foot of the asoarprient• Host of that at the 
top is due to fine material v/hioh is washed over from the 
summit and hold in place. This finer soil, coupled with 
the shadier conditions directly under the cliff, gives 
rise to a narrow strip of vegetation composed of a complex 
of spool os, some pioneer and some more or less mosophytic 
in char actor, -among the more important of these are Plnus 
atrobus . Plnus resinoSc . Quercus rubra t Prunus pennsylvonica . 
fopulus trenuloidos , Coanothus americonns , ?sodora quinque - 
folia, Rhus Toxicodendron , Oornus circinata . Khus typhina . 
Oolastrus scandens , Ostrya virgin!ana , Arctostaphylos Uva - 
ursi , and Symphorioarpos racomosus Miohx. var. pauciflorus 
Robbins. This plant assemblage, especially as regards the 
more mesophytic species, is only temporary, for as tho cliff 
recedes, the vegetation must recode with it. As tho height 
of the cliff becomes less, tho increased light and lessened 
degree of moisture make conditions intolerant for the more 
mesophytic si)ecies. Finally, with the disappearance of the 
escarpment, only xerophytic species are able to endure, 
such as occur on the more exposed portions of the smaller 
talus slopes. The border of tho forest forms a tension 



























































’ 


J e , . [ k. 










• ■ 

















- 

i.J* 



f 






































Pig* 37* - Lichens and moosoa on the talus slope (see 
fig* 35); the conspicuous foliose lichen is Parmelia conspersa; 
the throe Cladonius (lower right) are rangiferina . C. eyl - 
vatica and pyxldatu ; Hedwigia ciliata (extreme left)• 


































line at the bottom of the talus. Conditions for growth 
here are more favorable, not only on account of soil 
accumulation, but on account of the partial shade, -again, 
the pioneer species consist of lichens, which become more 
abundant here than higher up on the more exposed portions 
of the slope. By far the most conspicuous is Parmelia 
oonspersa . which covers the top of nearly every fragment 
of rook (fig. 37). The humus derived from this speoies 
paves the way for fruticose forms, such as Cladonla rangi - 
ferina (L. ) Hoffm., Cladonia sylvatioa (L.) Rabenh. and 
Cladonia pyxidata (L.) Hofffti. Following the lichens or 
sometimes closely associated with them are three species 
of moss, namely, Thuidium abietinum (L.) Br. & Sch., Hed- 
wigia oiliata iShrh. and Ceratodon purpureus (L.) Bride. 

The two fern species already mentioned, Po'lypodium vulgare 
and Woodsia ilvensis , follow the lichens and mosses. They 
are very common along the bottom of the talus slope, send¬ 
ing their roots down between the slabs, an early stage 
of the mesophytic forest may then follow directly as shown 
in fig. 36, where the talus is fringed by white birch. The 
conspicuous ommission of the usual mat stage here is due 
to the ability of the white birch to invade tho talus be¬ 
fore almost any other woody form. Clumping specimens with 
several stems often occur on the bare talus, sending thoir 
























. 

. 


■ : • * 

' 

, . - 










. 

. 

-i * - :w I ’• 






















Fig. 30. - An advanced stage in the in¬ 
vasion of the talus slope: note small size 
of rocK fragments (sandstone); pioneer tree 
species consist of Populua grandidentata . 
snail oaks ( Quercus rubra ), and small white 
pines ( Plnus -31 rob us ). 































































































































































































- .as .>j' 

























































-56 


roots far down between the fragments. In such cases they 
form nuclei for other pioneer speoies. Populus tremuloides 
and Populus grand!dontata are the pioneers along 3 ome parts 
of the forest front. 

as the cliff wears down and the talus elope becomes 
proportionately narrower, invasi on from both the bottom and 
top is accelerated (fig. 38). This is partially due to 
the fact that less new talus is put down, allowing the forces 
of weathering to establish a residual soil in which many 
speoies soon anchor themselves. One of the most efficient 
of these is Panicurn linear!foilurn Scribn. Evidence seems 
to show that it starts almost entirely by seeds from above. 
The warm nature of the talus soil, coupled with its moist 
condition during the early part of the season, must produce 
favorable conditions for germination of the many seeds which 
undoubtedly find lodgment there. Probably a very small 
percentage of tho seedlings are able to endure the very dry 
conditions which obtain during the summer. Other species 
of grass, such as Danthonia spioata , Qryzopsis Juneea, and 
Oryzopsis asperifolia also come in early. Arotostaphylos 
Uva-ursl and Aster maorophyllus L. form mats over the bare 
fragments, the latter plant being more prominent as con¬ 
ditions become shadier. Its large leaves form a very effect- 





































. 

. ■ ' 

• ‘ . _ . ' . - 

. 

: .. . ' ‘ - . . ; 

. 

. ‘ 

. 

: * 

y- - 

: cii - 


















- 


. 





























- 57 - 


ive mosaic 1-2 dm, above the surface, enabling more 
aesophytio species to start# .associated with these in 
varying proportions are tho brake ( uteris aoqullina h.), 
the sulmonberry ( Rubus parvifloruo Butt.) and the bush 
honeyoucklo ( Mervilla Lonicora rill#), the latter often 
being very common on the upper, dryer portions of the 
slope. 

The pioneer tree growth consists of small soattered 
individuals# If white birch be the pioneer spoolos, which 
seems not always to be the oase, it is soon followed by the 
poplar spocios alroady mentioned and by scrubby specimens 
of red oak# Besides many seedlings of the above, several 
other woody species appear more or less during the early 
stages of invasion such as hop hornbeam ( Ostryi virgin! an a 
frill #) k# koch#), arrow-wood ( Viburnum dent-turn L«)» choke- 
cherry ( krunus virglnlana L»). buffalo-berry ( Shepherd!a 
canadensis (L.) Butt.), Rubus procumbens lluhl., Rosa acicul - 
aris Lindl#, and seedlings of basswood, white ash and sugar 
mapla# 

Burly herbaceous species, as such, hardly form a 
definite stage in the succession in the sense of paving the 
way for woody growth# They may precede or accompany tfco 
latter, but are lator controlled by reaction# among the 
oonmoner species may bo mentioned Brigoron canadonsis L. 














































’ 


























- 



































































- 58 - 


(horseweed), Silene antirrhina L. (sleepy catolifly), Satur - 
oj a vulgaris (L.) Fritch. (basil), iiralia hispida Vent* 

(bristly sarsaparilla), Convolvulus spithamaeus L. (ereot 
bindweed), Carey adusta Boott., Antennaria neodioiea Greene 
(everlasting). Frag aria vasca L. var. amerioana Porter (wild 
strawberry), Bpilobiuro angustifolium L, (fireweed), Adlumia 
fungosa (ait.) Greene (climbing fumitory), Apocynum androesimi - 
folium L. (spreading dogbane) and Campanula rotundifolia L. 
(harebell). 

The sequence of the invading associations varies greatly 
at different points along the range. While Betula alba var. 
papyrifera is the dominant pioneer tree species at some points, 
at others it is Populuo tremuloides or Populus grandidentata . 
The exact ecologioal relationship between these three speoies 
is an interesting problem, but it was not worked out. Even¬ 
tually the invading forest merges with the permanent fringe 
of forest below the talus. The latter is often dominated 
by sugar maple and red oak, but here again considerable var¬ 
iation occurs, which will be considered later. 

(4) Forest below talus slope. 

This extends in general from the flood 
plain of the valley below to the bottom of the talus slope 
above, pushing up tov?ard the summit or even reaching it at 
low points in the range. It may vary in width from a mere 


































'. • . t i . . . 

; . ? r . . 

. 

. 

. .: 

. 

. 

. 

. 

•• 

, 

, 



























Pig* 39* - View of escarpment, looking north: vertical 
rock face about 70 m. high at tliia point; below this £00 - 
300 m* of talus material, being invadod by pines and aspens; 
below the talua elope iu the front of the advancing forest, 
which slopes to the valley of Carp River bolow* 





































. 

















»« 
















-59 


fringe of trees us ut A, fig. £6, to several hundred meters 
at P. While the trees species are mainly deciduous, espe¬ 
cially above, oonifers often occur near the bottom. These 
include white and red pine, balsam, arbor vitae, white spruce 
and hemlock. In fact, tlie last named speoies sometimes forms 
groves of large treos, similar to the climax forest of the 
north slope. 

A transect of the forested area was made at a point 
just east of the saddle in sec. 14. Hear the top, the 
talus slope was being rapidly invaded by small oaks and 

«» 

aspens, as shown in fig. 33, Populus grandidentata being the 
dominant species, intermingled with scattering white birch 
and maple saplings. A little further down, the open spaces 
became fewer, the trees taller (up to 15 m.), gradually form¬ 
ing a canopy above, giving perceptibly shadier conditions. 

The soil contained more humus, derived largoly from the 
leaves of the aspens. Here patches of Aster maorophyllus and 
Aralia nudicaulis formed a large proportion of the ground 
cover. Occasional small specimens of white ash, balsam, 
hop hornbeam, and basswood were noted as invaders at this 
stage. The unfavorable conditions for anchorage produce 
remarkable clumping of the stems in certain speoies, espec¬ 
ially in the sapling stage of the hop hornbeam, sugar maple 
and red oak. Wine stems were counted in one specimen of 






















i ' • “°- 

■ 

- 











: . ■ ; ' "• ' 

. 

: •• • ' 

. 
































Pig* 60* - Lower odge of foreot, bordering flood plain: 
the large tree in foreground io blade aeh; in the bacicground, 
Botula alba var* papyrifora . Bopulua tremuloidoa , Ac or rub rum . 
Cornua atolonifera. .hi!lx rootrata ana oalix petiolarie* 












































































































■ * 
































•• 

















hop hornbeam. Basswood overcomes the difficulty by ex¬ 
cessive sprouting. Approximately half way down the slope, 
a bench occurred, 15 - 20 m. wide, and nearly level. A 
striking feature hero was the appearance of rather large 
conifers, including specimens of white pine (up to 5 dm. 
dia.} balsam, white spruce, and arbor vitae. Poplar as 
the dominant species was replaced by red oak and white 
birch, ilore mesophytic oondi tions were indioatod by the 
presence of such species as Smilacina racomosa (L.) Desf. 
(false spikenard), Galium triflorum Iliohx. (sweet-scented 
bed straw), Hepatioa triloba Chair (liver-leaf), liaianthamum 
oanadense Pesf. (false lily-of-the-valley), Strootopus 
roseus Michx. (tv/is ted-stalk ) and Mitohella re pens L. (part¬ 
ridge-berry). Gradually the oaks were replaced by the sugar 
maple, which became the dominant species to the edge of the 
flood plain, with white pine still frequent as a subdominant. 
At the edgo of the forest bordering the flood plain, the 
increased light and moisture conditions produce a marked 
change in tho ground cover, with a great diversity of species 
coming in. Seedlings of aspen ( Populus tremulo ides) and 
hazel ( Oorylus rostrata ) seem to be responses to tho in¬ 
creased light. Tho frequent occurrence of wild black cherry 
( Prunus aorotina ) along the margin of the forest is undoubted 
ly a response to tho same conditions. Groves of aspon 














































J. 

. 

, • . • • 

r 

i; 

- - . 

« 





































. 









i 














fi/fc 



Fig. 41. - Gullying on south aide of first rung©, 
about halfway down the slope: white birch and aspen in 
the background; in the foreground, snail specimens of 
sugar maple and yellow birch; shoviu clumping specimens 
of hop hornbeam (upper right); ground cover mainly com¬ 
posed of Aralla nudicaulls. 





























































































' ' 




























61- 


saplings mixed with white hi rah aro not uncommon (fig.40). 

The appearance of many other woody species is due more to 
the itncreased moisture along the margin of the flood plain. 
Among these may he mentioned ffraxinus nigra Marsh. (black 
ash), Sal lx dipooler Kuhl• (glaucous willow). Viburnum 
Opulus L. (cranberry-tree), nlmus inoana (L.) Moench. 

(speokled alder), .acer rub rum L. (red maple), Spiraea salici - 
folia L. (meadow-sweet) and Cornus stolon! for a Llichx. (red- 
osier dogwood). 

l'he complex of ibrost and flood plain species is very 
variable in its composition. This may be explained partly 
by the very unstable conditions in the valley and partly 
by ohanges in the edaphio conditions produced by gullying 
down the side of the rungo, with the consequent deposition 
of new soil near the bottom of the slope. A noteworthy 
instance of the latter occurs opposite the saddle in sec. 

14 (fig. 41). Gullying in this case is due to the in¬ 
creased drainage over the saddle, resulting mainly from 
the melting snow in the spring. In the summer, its upper 
portion at least may be dry. 

II. Hydraroh successions in the valley of Carp River. 

As before indicated, the mesophytic forest be¬ 
low the talus slope is bordorod by Carp River or its flood 
plain. This flood plain is comparatively broad in the 

















V 

- 

t 

__ . ... _ - _. 

• - 




__ : 

. 

: : . . : : . ■ - 

J *■ 

k . . ; v - - 

• ' 

L . i * 

, I' • • 

, 



















Fig* 42* - "Cedar swamp" # north edge of Carp Kivor 
valley: the lurge trees near the center are arbor vitae 
( Thuja occidentalia ); the shrubs in the background are 
Alnus Inc ana , arid Cornua etolonifera * 


































































































































' 






























































































. 




























































-62- 


vicinity of the lake, due to the flat nature of the valley. 

At this point the river is a sluggish, meandering stream 
20 - 40 m. wide, doing very little vertical cutting, but 
shifting its course from time to time. Carp Lake is merely 
a broadened part of the river. According to Wright (28 ) 
the valley resulted not from the erosive action of a former 
river but to the pounding action of the waves on the shores 
of a vanished lake which covered the area. The present 
floor of the valley is subject to periodical flooding, in 
which a certain amount of sediment and debris from higher 
levels is laid down. There is thus a lack of stabilization 
in the edaphic conditions which prevents the encroachment 
of the mesophytic forest. The lino of demarcation between 
forest and flood plain is usually very abrupt, as shown in 
fig. 40. Flooding has the effect of producing irregularities 
and telescoping in the hydraroh successions paralleling the 
river, so that these successions are evidently not playing 
a prominent part in the formation of the forest. There are 
a few points along the range, however, where transitional 
bog forests may be found. One occurs between secs. 13 
and 18, T. 51 H. (fig. 42). This is near the mouth of a 
drainage system coming directly from the ridge. This 
forest is quite limited in extent. Its interest lies in 
the suggestion it gives as to the character of the bog 



, 

- 






• * ... , 




... 










• ■' • 







* 








. 


* . . -L‘ 


'' :t " ' ■ 





forest which will eventually procode the mesophytic 
forest as the latter claims the entire valley. The typical 
tree species are arbor vitae, white spruce, balsam, tamar- 
aoli and black ash. The forest floor is rough and often 
covered with a mass of shrubs, fallen logs and herbaceous 
growtli. The soil is typical muck, having a fine texture. 

In July the water table was approximately 3 dm. below the 
surface. Characteristic herbaceous plants are Aral!a 
nud i oaul i n . as tor naorophyllus . Galium asprollum Ilichx., 
Aspiflium crista tun (L.) Sw., Clintonia borealis fiJLt.) Raf •, 
Clrcaou alpinu L., Carox loptaloa .ahlerib., and Habenaria 
hyperboreu fL.) Rydb. 

The hydraroh successions of the river a nX flood plain 
contain many of the eloments of typical peat bog areas 
suoh us described by Davis flOa) for the Upper Peninsula. 

On the other hand, there is a lack of definitoness in the 
sequenoo of the associations; and the sphagnum element, 
with its accompanying vegetation, is not at all common. 

The latter condition is duo to the influx of fresh water 
during at least a portion of the year. A year of unusually 
high flood may destroy the continuity of vegetational 
development along cortain linos. This is well attested 
near the intake of Carp Lake by the dead und dying trunks 
of small black ash treos. Periods of exoessivo flooding 










































' 








■ 












. 




























































Pig* 43* - Carp Kivor from the summit of the first 
range, looking i»* 3* i£*: the river flows west, emptying 
into Carp Lake; flood plain in the distance covered by 
an alder swamp* 










■ 

- 










-64- 


may approximately be measured by the oldest of these. 

After such periods of high water, pioneer species again 
come in, initiating a new course of succession. A patch- 
work results, which is especially evident in the shrubby 
vegetation. This patchwork is further modified by the 
varying ability of the different species to withstand the 
presence of excessive water about their roots. The 
shorter-lived herbaceous forms often show more definite 
zonation, especially along such restricted areas as mud 
flats or sandy beaches bordering the river or lake. They 
are able to adapt themselves more readily to changing con¬ 
ditions. 

In order to illustrate the tendency of the hydraroh 
successions in the valley, the associations found in the 
river, lake and flood plain, will be briefly described. 

a. Carp River (fig. 42;. 

Where this stream flov^s through the 
flood plain it is comparatively shallow with a muddy 
bottom. The slow-moving current makes the ecological 
conditions very similar to those found along the margins 
of many of the smaller lakes in the Upper Peninsula. Among 
the immersed aquatics may be mentioned, Potamogeton pusillus 
L., Potamogeton heterophyllus Schreb., Potamogeton zosteri - 
folius Schumacher, Potamogeton amplifolius Tuckerm., 











£. ( ti l y err j *. 

. 

. . 

, .• . : : 

. 

, 

• ... 


■ •- . 

- 


* 













Fig* 44* - Carp Kiver near north edge of flood plain: 
the a3i rub lining the bank at this point is principally Ainu a 
inoana : the aquatics are Sparganiron euryoarpua and Mynphaoa 
advena; top of first range just visible in tho background 
(upper right)* 
















65- 


Potamogeton natans L., Myriophyllum Farwellii Morong., 

Ranunculus aquatilis L • var. oapillaoeue PC •, Hippuris 
vu lgari s L. 

The commonest large aquatic is Nymphaea 
advena Ait. (yellow pond lily); it sometimes forms patches 
extending half way across the stream. Castalia tuberosa 
(Paine) Creene (white pond lily) is much less common, 
though it occasionally occurs in large patches; the same 
may he said of the water-shield ( Brasenia Schg&beri Gmel.). 

In many places the stream is fringed with overhanging shrubs 
as shown in fig. 44. Mud banks often occur at the bends, 
supporting various aquatic or amphibious species, such as 
Potentilla palustris (L.) Scop, (marsh cinque-foil), 
Sparganium ey ryoarpum Engelm. (bur-reed)., Bleocharis 
aoicularis (L.) R. & S. t Carex filiformis Good, (bog sedge) 
and Car ex striota Lam. The last two species form clumps 
at various points along the bank, thus enabling other species 
to obtain a footing. 

The shrubby growth along the banks 
consists principally of the following:- ALmus incana (L.) 
Moench. (hoary alder). Hex verticillata (L.) A. Gray (win¬ 
ter-berry), Cornus stolonifera Miohx. (red-osior dogwood), 
Chamaedaphne calyculata (L.) Moench. (leather-leaf). 

Spiraea salioifolia Roi (meadow-sweet), Salix petiolaris 







































... •• 






. • 


. 




• .- - 

.... - -• —■ 

_ 2 ♦ • 

’ -• - * . .I'_ ••• 

* 


. 

. : - ' . . .. ■ • - 

,1 : J.... ... • 

. 









































66 - 


Sol lx pedicellarls ?ursh (bog willow) and 
lucida iiuhi. (shining willow)* Two fern species, 
namely Osmund a regalia L. and Aopidium Tholypterls (L.) 

Sw *» often occur at the margin of the water, more or lees 
shaded by the shrubs. Ciianaod aphno calvculata . though 
not the commonest shrub lining the river bank, is pro¬ 
bably the moat important in the formation of floating 
mats, these often starting from sedge hummocks. One 
effect of the mats is to cut off quieter bodies of water 
where various aquatic and amphibious specios are more success 
ful in establishing themselves. 

One thing seems clear in connection with the 
successions along the margin of the river, namely their 
instability. Kven when Carp Lake as such, is gone, the 
river will still continue, though not in its present bed, 
as the bottom of the valley will have been raised through 
sedimentation. 

b. Carp Lake (fig. 1)• 

The lake lies parallel to the main ridges, 
covering the floor of the valley for a distance of about 
2 km. Its broadest portion is near the east end, where 
it has u width of approximately 0.5 km. Excepting at 
this end, the nesophytic foest oxtends nearly to the 
water*s edge. At the east end a broad delta has been 















































' 

































' 


«• .... I 

N 
























































Pig. 45. - Delta, east end of Carp Luke, looking east: 
in the foreground, aclrpus occidentulis t aquisetura fluviatlle , 
and flypphaoa advena ; narrow channel of tho river shown in the 
background; first range in the distance, showing saddle in 




section 14 































-67- 


forraed, where Carp River enters the lake (fig# 45). The 
submerged part of the delta extends well out into the lake, 
being several hundred meters broad at its widest portion 
(fig. 46). Hero the water is shallow, varying from 3-10 
dm. in depth. The west end of the lake is also shallow, 
and ohoked with aquatic growth and debris, especially near 
the outlet. In general the beaches are very narrow. Most 
of those on the north side are of the shingle type. In 
places they are entirely lacking, the shore line being 
directly bordered by a fringe of shrubs similar to those 
along the bank of the river. Sandy beaches occur on the 
south side and near the west end on the north side. They 
are broader than the gravel beaches and show more clearly 
the zonal development of vegetation. The edaphic con¬ 
ditions are naturally more stable around the margin of 
the lake than along the river. Especially is this true 
on the south side where deposition is occurring more rapidly 
than on the north. 

The free-floating aquatic vegetation of the 
lake, being very similar to that of the river, need not be 
mentioned. The best evidences of plant succession are seen 
on the flat sandy beaches and on muddy flats near the 
delta. At the delta there is a zone of rushes extending 
from 50 - 100 m. out into the lake. Its outer part consists 












■ 

... 


. 








e .. . ■ ■ ■ • ' 

' *- ’ 






* 






Fig* 46* - iSast end of lake, looking south toward second 
range: the zone of rushes ( Sclrpua cceidentulis ) marks the 
shallow water over the submerged portion of the delta; the 
group of balsams along the opposite shore indicates the pres¬ 
ence of a small stream flowing into the lake* 



























-u8- 


of the bulrush ( Scirpu3 occldentalis (Wats.) Chase; then 
comes a zone of Equisetum fluviatlle L. (pipes) covering 
a large area. The inner portion of the zone consists of 
a mixture of Glyoeria borealis (Nash ) Batohelder (northern 
manna grass), Leersia oryzoides (L.) Sw. (rice cutgrass), 
and along the muddy shore Eleocharis palustris (L.) R. & 

S., Acorus Calamus L. (sweet flag), Dulichium arundinaceum 
(L.) Britton, Polygonum amphibium L. (water smartweed), 
Glyoeria canadensis (Miohx. ) Trin. (rattlesnake grass), 
Solypus atrovirens Muhl., Eleooharis obtusa (Willd.) Schultes 
(blunt spike-rush) and Saglttaria latifolia L. form& Gracilis 
(Pursh) Robinson, apparently the common form in northern 
Michigan. The immediate shore is fringed with clumps of 
Salix lucida , interspersed with open areas covered with 
Oalamagrostis canadensis (Miclix.) Beauv. (bluejoint). Logs 
lying almost concealed tell the story of flooding at this 
point; this is also shown by standing specimens of Alnus 
inoana and Salix petiolaris , dead above, but making vigor¬ 
ous gew growths at the base. 

In the shallow water bordering the sandy 

beaches, the rushes are often accompanied by areas of pipe- 
wort ( Eriocaulon artioulaturn (Huds.) Morong. This may 
produce unusually long stems when growing with Soirpus 
occidentalism Among the commoner species occurring on the 














































. 


* •. 








. . . .. ■ . 

' . . . < •• . 

. 

- — -.- —- - ~ - 

. 






.J V 

. ' « ’ 

' 

... . . . ■ . . ... 











* 



, 

. 


. 

















































-69- 


sandy beaches are the following:- Juncus brevicaudatus 
(iSnglem*) Pernold, Hypericum elliptlcum Hook* (pale St* 
John's wort), Cladiun nariscoidos Terr* (twig-rush), 
Ranunculus Plemcmla L. (smaller spearwort), Him ulus ringens 
L* (nonkey flower), Slum cloutaefollnm Schrank (water 
parsnip), Agrostia hy emails (Walt.) BSP* (hair grass). Carex 
erinita Lam*, Carex rostrata Stokes, and Carex Ooderi Betz. 
Both the sandy and gravelly beaches are very often backed 
by a shrubby association composed of 6hamaedaphne calyou - 
lata . Ilex verticlllata . and nlnua Incana * With these often 
occur Spiraea salicifolia and Praxinus nigra , fringing tho 
mesophytic forest. 

It is evident from tho above description 
that tho transition from lake to mesophytic forest is rather 
abrupt; this is especially true on the north side of tho 
lake, where the angle of slope is greatest* The few asso¬ 
ciations notod along the narrow beaches consist of plants 
which are able to endure submergence for brief periods. The 
shrubby growth backing the beaches, though only a little 
above the mean level of the lake, is high enough to escape 
mostly the destructive influences of high water. 

c. Blood plain. 

On account of tho varying influence to 
which the flood-plain is subjected, the successions are not 






































.. 






























































' 
















* i 





































-70- 


in general, well marked. In the broader portions of the 
valley, as in ooo. 24. ?. 61 H. R. 43 W.. there is a dense 
growth of Alnua Incana. intermingled with occasional in¬ 
dividuals of tamarack. In the northwest corner of the above 
section there is a small "tamaracK swamp", forming a typical 
stage in the filling up of a peat bog. The ecological stages 
of such a bog have been well described by Transeau (25), 
Cooper (5), and others and will not be treated here. In 
sections 23 and 14, immediately east of the lake, the flood- 
plain is covered by a grassy marsh (fig. 40), with a shrubby 
zone lining the river, as already described. The flora of 
this area is very composite in character. Portions of it 
are dominated by a dense growth of blue joint ( Calamagrostls 
canadensis). The list of specios observed here includes 
the following: - Ascloplas incarnata L., Verbena hast at a L., 
Aster punlceus L., iSupatorlum purpureum L., Sclrpus Cyperlnus 
(L.) Aunth., Osmunda regalis L., Onoclea aenslbillfe L., 
Solidago aerctlna Ait•, Anemone canadensis L., Chelono glabra 
L., Aapldium Thelyptorlo (L.) Sw., Pteris aquillna L., 

Glyceria canadonsis (Hichx.) Trin., Lysimachla torrestria 

N 

(L.) BSP., Iris versicolor L. 9 Cicuta bulbifera I., Suutel - 
laria lateriflora L., Thaiictrum dasycarpum Fisch. & Lall., 


Galium asprollum Hichx., Conn strictum Ait., Impatlens bi ¬ 
flora Valt., Hum ex vertic Hiatus L., Hypericum vlrglnloum I., 





























































. 

■ 

. ■ 

. 

. 





. 

* 






• . 1 



















-71 


Campanula ullginosa Rydb• f Phalarls arundi nacea L. , Clematis 
virgin!ana L., Leersla oryeoldes ( L•) Sw •, Kumulus Lnpulus 
I<« , Ranunculus Pennsylvania us L. f., Gal ium Clayton! Miohx., 
Radioula palustris (L.) Moench., Garex filiformis L., and 
Oarex tribuloides Wahl* 

The grassy marsh described above un¬ 
doubtedly oocupies the position of a former delta. It 
thus represents a stage in the gradual filling up of the 
valley with sediment and organic remains. 


STOIMAHI 

The ranges of the Porcupine Mountains are 
entirely surrounded by a low plain, so that the mountains 
were islands for some time after the final retreat of the 
ice sheet. As the water subsided, the higher ranges to 
the south were first uncovered. Pioneer invasion probably 
took place where the wash of the waves was not too severe, 
following stages analagous to those found in the present 
shore line. At the present time,these southern ranges or 
hills, including Government Peak, the highest point, are 
clothed with a mesophytio forest to the very top (fig. !)• 
This mesophytio forest was possibly preceded by a zero- 
phytic coniferous forest dominated by pine species, as 


























T' 

••P 


. ' ‘ 




. 


; • * 

















\ , . : • 



; .. , 



-■ » 

v ’ - . 


• 

.... 




• 



r ^ 


•' i 01 1 •. 

s. i . ■■ 




r 

• 

•: . 1 



* 

• * . 

■ 

.. . 


• 





W V V 





' - . . ... «,,» 1 

t 





. * . *. * * •• 



, 




, .... 

• 


. * * 

• 


- 


~ • 


» ' C 

• 

«■ « • . 


.* . 

t 



* /* r 
























72- 


suggested by Ruthven fl,p. 27). In this ease the pines 
began their invasion near the water's edge, following the 
heath mat stags# They made their last stand at the top 
of the mountains, being followed up and replaced by a 
mesophytio fbrest, the successions being correlated with 
the greater accumulation of soil near the base of the 
slope. 

The top of the first range is unique in still 
holding out against the mesophytio forest. This is un¬ 
doubtedly due to the peculiar topography of this range. 

As is evident from fig. 3, this topography is associated 
with the presenoe of Carp Lake, which once covered a much 
greater area than at present. The ddp of the strata to¬ 
ward the north, coupled with the subsidence of Carp Lake, 
has created a great cliff or escarpment, which is con¬ 
tinually wearing away, producing a talus slope at its foot. 

The development of vegetation over the region 
has led to two climax formations, namely the hemlock climax 
and the maple climax. 

The presence of the hemlock climax on the north 
elope of the first range seems to be conditioned by the 
physical factors of temperature, moisture and light. Great¬ 
er humidity and more uniformity in temperature noar the 
shore is due to the presenoe of a largo body of water. The 








; 


. p 


' 

. . t 

. t " 5 .%•». 

* 




: i Lj. i 

f • 

- • 


• 





s. * 

* 



L 0 

• 

■ 



: .. :: ~>7. 

• ■ • : 






l< i 




. 

cl' ■ '2 

i : ■ no ' ' ! '■ : 

.f i I • •. : • J ' 

-- •• • . . ■ •• *- r •• 










*. o 


- ' i > * • ■ 

X ■ ■ 








V . 






, • : 


* *' 
- - 


- : - . : H S 

, 


• :• • ... V- ~ v;: 








* * J .* * - 










■- J . 






. 






. . . j. 

.. / .. •- -* <*• * „-v * * 

J . '• ; • : i 










. . * 

1 ■ J * v 




average temperature of points along the coast is several 
degrees warmer than inland points a few miles bach, and 
the average precipitation during the winter months is 
30/ii more than at Bergland, 26 km* hack from the shore* 
Keduced light intensity at the lower, more humid elevations 
on the north slope is probably more favorable to hemlock as 
compared with maple. 

The maple climax occurs on the higher portions 
of the first range (excepting the summit) and on the ranges 
further south. As compared with hemlock, maple seems to be 
more tolerant of extremes of temperature and light. 

The principal succession leading to the hemlock 
climax is along the shore. The pioneers in the more exposed 
situations are erevioe plants. In the severer situations 
tliese can initiate only very short or incomplete lines of 
succession. Where conditions are less severe, which may 
be only a few meters further inshore, the pioneers consist 
of lichens, mosses and crevice plants, which lead to more 
definite lines of advance; but the irregularities of the 
shore line produce such varied conditions that there is 
often a lack of any gradual transition from lower to higher 
ecological forms. At practically all points along the shore, 
the climax forest has pushed down to the limit of its 
possible extension undor present conditions; and this has 




.■ - ■ :■ • - 

>: 

. . . . . . ■ . . 

. 






. ■ f * 

• i ' : -l 

. - : • 

. -V ... _. v.. • . i: . .... -o . ... ; • - 

. • • 

, 

r . •. . • v.. :• :• ; 

. 

; •, . 

, * . 

• • i - . . : • .i ' • ' • > 

• * • 

it L li - \ ' . * • •'.! 

L -i . , i„ O ' ■ X .. • 

• . • . . . ' 












74- 


resulted in a telescoping of the ordinary transitional 
stages• 

Lines of succession leading to the maple climax 
may be seen at the summit of the first range and in the 
valley of Carp River. In the first case the climax is 
reached through xerarch series, beginning with crustose 
lichens and xerophytic mosses on the exposed rock surface 
of the summit. One of the principal pioneers is Selaginella 
rupestris « which often forma a layer of humus 1-2 dm. 
thick. This together with various low-growing species, in¬ 
cluding crevice plants such as Danthonia spicata and Panicurn 
depauperatum . paves the way for the heath mat, which is 
composed largely of two species of Vaccinium (see text). A 
zone of scrubby conifers and oaks then leads gradually to the 
maple climax on the north side of the summit. 

On the south side the presence of the cliff 
forms a direct barrier to invasion from below, except where 
the escarpment has been worn down so as to produce a saddle 
aoross the range. Below the escarpment there is a talus 
slope of varying width, fringed by a mesophytic forest ex¬ 
tending below to the flood plain of Carp Hiver. In general 
this mesophytic forest is young and heterogeneous in char¬ 
acter, but it is approaching the maple climax. Its upper 
border is irregular, but forms a more or less sinuous 






















' 



. 
















. 













































-75- 


curve representing a line of invasion on the talus. Since 
the width of the talus depends on the height of the escarp¬ 
ment, the line of invasion extends high at low points in 
the range. 

Suocessional continuity on the talus is more 
or less broken, at least in the earlier stages. Lichens 
and certain moss species are undoubtedly important, but 
Betula alba var. papyrifera is one of the noteworthy pioneers 
adapting itself to unuaually severe conditions. This is 
followed sooner or later by aspens, after which there is a 
gradual transition toward the mesophytic climax. 

As the cliff wears down the summit of the range 
will eventually be claimed by the mesophytic forest. At 
present the xerarch series forms a connecting link between 
the maple climax in the valley and on the north side of the 
summit. 

The lower edge~ of the mesophytic forest below 
the talus forms an abrupt border to the flood plain of 
Carp River. This is due to periodical flooding, which 
produces irregularities and telescoping throughout the 
hydrarch series on the comparatively flat floor of the 
valley. Any marked building up of the mesophytic climax 
from this source must therefore await a change in physio¬ 
graphic conditions along the river valley. This will 











.| . *' * r 
. 












. 























mesophytic fores t 
(m^-ple cl/md.X) 



Fig# 47. - Diagram shewing linos of vogatational 
development leading to the maple climax on the first 


range. 



























































. 








. 












































































-76- 


oome with the gradual filling up of the valley through 
sedimentation, thus changing* the conditions under which 
flooding now ocours. The present successions along the 
valley of Carp River and Carp Lake aro of comparatively 
little moment; however they indicate the character of a 
portion of the hydruroh series which will eventually lead 
to a mesophytic climax covering the entire floor of the 
valley* 

The principal * ones of vegetation in connect¬ 
ion with the development of the maple climax on tho first 
range are shown in the diagram (fig* 47). The letters 
a, b, £, d, indicate the lines of succession. The line £ 
begins with lichens, mosses,and crevice plants at the bare 
summit, and culminates in the maple forest on the north 
elope; b originates largely from seeds washing over the N 
summit; £ represents a line of invasion on the talus slope 
from Ihe forest below; d is a broken line representing the 
discontinuous nature of the hydrarch succession from the 
valley of Carp River. Part of this succession leads to the 
mesophytic forest on the second range. 


















; . . 







. 




I : 




* . 

. 2 ’ V '• ; v 

. 





; , ■ • - 

. ;? * ' ' ". - . . . v -1 1 

.* •: . : ' '• i- 







. 














77- 


-RKFERENCE8- 

1. ADAMS, C. C., An ecological survey in northern Michigan. 

A report from the University Museum, University 
of Michigan, published, by the State Board of Geo¬ 
logical Survey as a part of the report for 1905. 
Lansing, Mich. 1906. Part I, pp. 17 - 47, written 
by Dr. A. 0. Ruthven, deals with the general 
ecological relations of the Porcupine Mountains, 
and pp. 75 - 92 contain notes on the flora of 
these mountains. 1905. 

2. BEAL, W. J., Observations on successions of forests in 

northern Michigan. Rep. Mich. Forestry Comm. 

1:25 - 29. 1888. 

3. BURT, W. A., Catalogue of the plants collected in the 

primitive region south of Lake Superior in 1846. 

D. Cooley, Jackson’s Lake Superior, pp. 875 - 
882. Washington, D. C. 

4. CLEMENTS, F. E. , Plant Succession, An Analysis of the 

Development of Vegetation. Publ. 242, Carnegie 
Inst. Wash. 1916. 

5. COOPER, W. S., The climax forest of Isle Royale, Lake 

Superior, and its development. BOT. GAZ. 55:1 - 
44, 115 - 140, 189 - 235. 1913. 

6. COWLES, E. C., The physiographic ecology of Chicago 

and vicinity. BOT. GaZ. 31:73 - 108, 145 - 182, 



1001 


, r . . ; .Wx 














, # • • 


: 


f 












. 












; - , . i- ‘ 









- 78 - 


'• __» The influence of underlying rooks on 

the character of the vegetation. Bull. Amer. 

Bur. Geog. 2:1 - 26. 1901. 

8* _, The causes of vegetative cycles. BOT. 

GAZ. 51:161 - 185. 1911. 

The physiographic ecology of northern 
Michigan. Science 12:708 - 709. 1900. 

10. DaRLILGTOL, H. T., Contributions to the flora of 

Gogebic County, Michigan. 22nd Rep. Mich. Acad. 

Soi. 1920, pp. 147 - 176; Mich. Aoad. Sci., Arts 
and Letters, Vol. 1, pp. 74 - 82. 

10a. DAVIS, C. A., The formation, character and distribution 

of peat bogs in the northern peninsula of Michigan. 
Mioh. Geol. Survey. 1906. 

11. FOSTER, J. W., and WHITLEY, J. D., Report on the geology 

and topography of a portion of the Lake Superior 
land district, in the state of Michigan. Exec. 

Doc., 1st Sess., 31st Co#g. Vol. 9, part 1. 1850. 

12. _, Report on the geology of the Lake Superior 

land district. Part II, the iron region. Sen. Doc., 
Spec. Sess., 32d Cong. Vol. 3, 1851. Contains a 
list of plants from the Upper Peninsula, including 
some from the Porcupine Mountains. 






















. 

, « , 

: ' * . ‘ 






* 

. « 




. 






















-79- 


13* FROTHIHGHAM, E. H., The northern hardwood forest; its 
composition, growth and management* Bull. 285, 
Contrib. For. Serv., U. S. D. A* 1915. 

14. _, The eastern hemlock. Dept. Bull. 

152, U. S. D. A. 1915. 

15. FULLER, G. D., Evaporation and soil moisture in relation 

to the succession of plant associations. BOT. GAZ 
58:193 - 234. 1914. 

16. GLEASON, H. A., The structure and development of the 

plant association. Bull. Torr. Bot. Club, 44:463 
481. 1917. 

17. GRAVES, H. S., The study of natural reproduction of 

forests. Forestry Quart. 6:115 - 137. 1908. 

18. ENECHTEL, A., Natural reproduction in the Adirondack 

forests. Forestry Quart. 1:50 - 55. 1903. 

19. LANE, A. C. , The Keweenaw Series of Michigan. Mich. 

Geol. and Biolog. Survey. 1911. 

20. LEVERETT, Frank, and TAYLOR, Frank B., The pleistocene 

of Indiana and Michigan and the History of the 
Great Lakes. U. S. Geol. Survey. Monograph 53. 
1915. 

21. MOORE, B. , Reproduction in coniferous forests of 

northern New England. B0T« GAZ. 64:149 - 158. 


1917 








. - 


. . . . * . 




* 


. 






* 








l ■ 

- . - : , 




‘ 










. 

. . : 

..... • 

- 






* 








. 

, 


. < ' . . ... 




. 






./ 

• • 


























-80- 


22. ROBINSON, B. L., and FERNALD, M. L. , Gray* s Manual 

of Botany. Ed. VII. New York. 1908. 

23. RUTHVEN, A. G., Notes on the plants of tho Porcupine 

Mountains and Isle Royale, Michigan. In ADAMS 

( 1 ). 

24. SEELEY, D. A., The Climate of Michigan. State Dept. 

Agr. , Lansing, Mich. 1922. 

25* TRANSEAU, E. N. , On the geographical distribution and 
ecological relations of the bog plant societies 
of North America. BOT. GA2* 36:401 - 420. 1903. 

26. WHITFORD, H. N., The genetic development of the forests 

of northern Michigan. BOT. GAZ* 31:289 - 325. 
1901. 

27. WHITTLESEY, Col. Chas. , A short account of the Por¬ 

cupine Mountains, Eng. and Mining Jour., Vol. 

23, p. 254. Apr. 1877. 

28. WRIGHT, F. E., Report on the progress made by the 

Porcupine Mountain party during the summer of 
1903. Ann. Rep. Mich. Geol. Survey 1903, pp. 

36 - 44. 

29. ZON, Raphael, Principles involved in determining 

forest type8. Forestry Quart. 6:263 - 271. 


1908. 





- 

„ H f irll * i ' *- Lr 

v: • r " #< 1 




. . ' • • * - 






. 




* 











































































































































































































































